MRNA VACCINES ENCODING FLEXIBLE CORONAVIRUS SPIKE PROTEINS

RELATED APPLICATION

This application claims the benefit under 35 U.S.C. § 119(e) of the filing date of U.S. Provisional Application Serial Number 63/210,436, filed June 14, 2021, the entire contents of which is incorporated herein by reference.

BACKGROUND

Human coronaviruses are highly contagious enveloped, positive sense single-stranded RNA viruses of the Coronaviridae family. Two sub-families of Coronaviridae are known to cause human disease, the most important of which are the //-coronaviruses (betacoronaviruses). The //-coronaviruses are common etiological agents of mild to moderate upper respiratory tract infections; however, outbreaks of novel coronavirus infections, such as the infections caused by a coronavirus initially identified from the Chinese city of Wuhan in December 2019, have been associated with a high mortality rate death toll. This novel coronavirus, referred to as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) (formerly referred to as a “2019 novel coronavirus,” or a “2019-nCoV”) has rapidly infected millions of people. The pandemic disease that the SARS-CoV-2 vims causes has been named by World Health Organization (WHO) as COVID-19 (Coronavirus Disease 2019). The first genome sequence of a SARS-CoV- 2 isolate (Wuhan-Hu-1; USA-WA1/2020 isolate) was released by investigators from the Chinese CDC in Beijing on January 10, 2020 at Virological, a UK-based discussion forum for analysis and interpretation of virus molecular evolution and epidemiology. The sequence was then deposited in GenBank on January 12, 2020, having Genbank Accession number MN908947.1. Subsequently, a number of SARS-CoV-2 strain variants have been identified, some of which are more infectious than the initial SARS-CoV-2 isolate.

Currently, there is no specific treatment for COVID-19 or vaccine for later-emerging SARS-CoV-2 variants. The continuing health problems and mortality associated with coronavirus infections, particularly the SARS-CoV-2 pandemic, are of tremendous concern internationally. The public health crisis caused by SARS-CoV-2 and its variants reinforces the importance of rapidly developing effective and safe vaccine candidates against these viruses.

SUMMARY

Provided herein, in some embodiments, are messenger ribonucleic acid (mRNAs) encoding highly immunogenic SARS-CoV-2 spike (S) protein antigens capable of eliciting potent neutralizing antibody and immune cell responses against coronaviruses (e.g., SARS-CoV- 2, SARS-CoV, MERS-CoV, HKUl-CoV, M-CoV, or NL63-CoV). The mRNAs described herein are used to express coronavirus S protein with various glycine substitutions (e.g., L984G, D985G, K986G, and/or V987G of the SARS-CoV-2 S protein (USA-WA1/2020 isolate)) and/or proline substitutions that display improved immunogenicity.

The envelope S proteins of known betacoronaviruses determine the virus host tropism and entry into host cells and are critical for SARS-CoV-2 infection. The organization of the S protein is similar among betacoronaviruses, such as SARS-CoV-2, SARS-CoV, MERS-CoV, HKUl-CoV, M-CoV and NL63-CoV, including two subunits, SI and S2, which mediate attachment and membrane fusion, respectively. Without wishing to be bound by theory, it is thought that the substitutions described herein, which occur in the S2 subunit, disrupt helix formation, and allow increased flexibility within the domain.

Some aspects of the present disclosure provide a messenger ribonucleic acid (mRNA) comprising an open reading frame (ORF) that encodes a modified coronavirus spike (S) protein, wherein the spike protein comprises at least mutations and wherein at least one of the two mutations is a glycine mutation.

In some embodiments, the mRNA further comprises 1-8 additional mutations (e.g., 3-10 total mutations). In some embodiments, the at least two mutations comprise 2-10 glycine mutations. In some embodiments, the at least two mutations comprise four glycine mutations. In some embodiments, the at least two mutations comprise at least one proline mutation. In some embodiments, the at least two mutations are substitutions. In some embodiments, the at least two mutations comprise four glycine substitutions. In some embodiments, the at least two mutations are insertions. In some embodiments, the at least two mutations comprise at least one substitution and at least one insertion.

In some embodiments, the at least two mutations are located in the S2 subunit of the coronavirus spike protein. In some embodiments, the at least two mutations are located between the heptapeptide repeat sequence (HR) 1 and HR2.

In some embodiments, the modified coronavirus spike protein is a modified version of a coronavirus selected from the group consisting of: SARS-CoV-2, SARS-CoV, MERS-CoV, HKUl-CoV, M-CoV and NL63-CoV.

In some embodiments, the modified coronavirus spike protein is a modified of SARS- CoV-2. In some embodiments, the mRNA encodes a SARS-CoV-2 S protein having at least two mutations at positions L984, D985, K986, and V987 relative to a SARS-CoV-2 spike protein comprising the amino acid sequence of SEQ ID NO: 15. In some embodiments, the mRNA encodes a SARS-CoV-2 S protein having four mutations at positions L984, D985, K986, and V987 relative to a SARS-CoV-2 spike protein comprising the amino acid sequence of SEQ ID NO: 15. In some embodiments, the mutations are glycine mutations. In some embodiments, the mutations are glycine substitutions. In some embodiments, the mutations are glycine and proline mutations.

In some embodiments, the mRNA encodes a modified protein having >90%, >91%, >92%, >93%, >94% >95%, >96%, >97%, >98%, or >99% sequence identity (e.g., global sequence identity, e.g., identity over the entire or full length protein sequence (for example the amino acid sequence of SEQ ID NO: 15)), wherein the modified protein comprises glycine at least at 2, 3, or 4 of L984, D985, K986, and V987.

In some embodiments, the mRNA encodes a modified protein having >90%, >91%, >92%, >93%, >94%, >95%, >96%, >97%, >98%, or >99% sequence identity to the amino acid sequence of SEQ ID NO: 15, wherein the modified protein comprises glycine at least at L984, D985, K986, and V987.

In some embodiments, the mRNA encodes a modified protein having >90%, >91%, >92%, >93%, >94%, >95%, >96%, >97%, >98%, or >99% sequence identity to the amino acid sequence of SEQ ID NO: 8. In some embodiments, the mRNA encodes SEQ ID NO: 8.

In some embodiments, the ORF has at least 90% or at least 95% or at least 98% identity to the nucleotide sequence of SEQ ID NO: 7.

In some embodiments, the ORF comprises the nucleotide sequence of SEQ ID NO: 6.

In some embodiments, the mRNA comprises a 5’ untranslated region (UTR) comprising the nucleotide sequence of SEQ ID NO: 2.

In some embodiments, the mRNA comprises a 3’ UTR comprising the nucleotide sequence of SEQ ID NO: 3.

In some embodiments, the mRNA comprises the nucleotide sequence of SEQ ID NO: 6.

In some embodiments, the mRNA further comprises a chemical modification.

In some embodiments, the chemical modification is 1-methylpseudouridine.

The disclosure, in some embodiments, provides a composition comprising any one of the mRNAs described herein and a lipid nanoparticle.

In some embodiments, the lipid nanoparticle comprises a PEG-modified lipid, a non- cationic lipid, a sterol, an ionizable amino lipid, or any combination thereof.

In some embodiments, the lipid nanoparticle comprises 0.5-15 mol% PEG-modified lipid; 5-25 mol% non-cationic lipid; 25-55 mol% sterol; and 20-60 mol% ionizable amino lipid.

In some embodiments, the PEG-modified lipid is 1,2 dimyristoyl-sn-glycerol, methoxypoly ethyleneglycol (PEG2000 DMG), the non-cationic lipid is 1,2 distearoyl-sn- glycero-3-phosphocholine (DSPC), the sterol is cholesterol, and the ionizable amino lipid has the structure of Compound 1 :

(Compound 1).

Other aspects of the present disclosure provide a method comprising administering to a subject the mRNA of any one of the preceding claims in an amount effective to induce a neutralizing antibody response (e.g., against SARS-CoV-2) in the subject.

In some embodiments, the subject is immunocompromised and/or has a pulmonary disease. In some embodiments, the subject is seronegative or seropositive. For example, a subject may be naive and not have antibodies that react with SARS-CoV-2 or may have preexisting antibodies to SARS-CoV-2 because they have previously had an infection with SARS-CoV-2 or may have previously been administered a dose of a vaccine (e.g., an mRNA vaccine) that induces antibodies against SARS-CoV-2. In some embodiments, the vaccines described herein may be the only vaccine comprising a nucleic acid encoding a SARS-CoV-2 antigen that a subject receives. Alternatively, any one of the vaccines described herein may be administered in combination with other vaccines comprising a nucleic acid encoding a SARS- CoV-2 antigen, as a prime and/or boost dose.

The entire contents of International Application No. PCT/US2016/058327 (Publication No. WO 2017/070626) and International Application No. PCT/US2018/022777 (Publication No. WO 2018/170347) are incorporated herein by reference.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows titers of IgG specific to a SARS-CoV-2 Spike protein with two proline substitutions. Sera were obtained from mice administered PBS or 0.1 pg or 1 pg mRNA encoding SARS-CoV-2 Spike protein with four glycine substitutions (SEQ ID NO: 6). The light circles shown data from Day 21 (3 weeks post-prime) and the dark circles show data from Day 36 (two weeks post-boost). Data for PBS and for mRNA encoding a SARS-CoV-2 Spike protein antigen having a double proline mutation (mRNA-1273) are also shown.

DETAILED DESCRIPTION

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly emerging respiratory virus with high morbidity and mortality. SARS-CoV-2 has spread more rapidly around the world compared with SARS-CoV, which appeared in 2002, and Middle East respiratory syndrome coronavirus (MERS-CoV), which emerged in 2012. The World Health Organization (WHO) reports that, as of September 2020, the current outbreak of COVID-19 has approximately 32 million confirmed cases worldwide with nearly a million deaths. New cases of coronavirus disease 2019 (COVID-19) infection are on the rise. It is thus crucial that a variety of safe and effective vaccines and drugs be developed to prevent and treat COVID-19 and reduce the serious impact that COVID-19 is having across the world. Vaccines and drugs made using a variety of modalities, and vaccines having improved safety and efficacy, are imperative. There remains a need to accelerate the advanced design and development of vaccines and therapeutic drugs against COVID-19.

On January 7, 2020, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the etiological agent of a novel pneumonia that emerged in December 2019, in Wuhan City, Hubei province in China (Lu H. el al. (2020) J Med Virol. Apr; 92(4):401-402.). Soon after, the vims caused an outbreak in China and has spread to the world. According to the analysis of genomic structure of SARS-CoV-2, it belongs to b-coronavimses (CoVs) (Chan et al. 2020 Emerg Microbes Infect .; 9(l):221-236).

A key protein on the surface of coronavirus is the spike protein. When formulated in appropriate delivery vehicles, mRNA encoding spike antigen induces a strong immune response against SARS-CoV-2, thus producing effective and potent mRNA vaccines. The modified proteins of the SARS-CoV-2 S protein and other CoV S proteins provided herein, (e.g., comprising one more glycine and/or proline substitutions, for example L984G, D985G, K986G, and/or V987G), are more flexible than their parental SARS-CoV-2 or other CoV S proteins. The enhanced flexibility of SARS-CoV-2 and other CoV 2 proteins is thought to elicit antibody responses to a broader range of S protein epitopes, further improve vaccine efficacy at the same dose, and/or maintain efficacy at lower doses. Administration of the mRNA encoding S protein antigens, such as the various modified forms of the prefusion stabilized spike protein antigens described herein, results in delivery of the mRNA to immune tissues and cells of the immune system where it is rapidly translated into protein antigens. Other immune cells, for example, B cells and T cells, are then able to develop an immune response against the encoded protein and ultimately create a long-lasting protective response against the coronavirus. Low immunogenicity, a drawback in protein vaccine development due to poor presentation to the immune system or incorrect folding of the antigens, is avoided by using the highly effective mRNA vaccines encoding spike protein as disclosed herein. Therefore, the vaccines described herein may be used to induce a balanced immune response, comprising both cellular and humoral immunity. Such a vaccine can be administered to seropositive or seronegative subjects. For example, a subject may be naive and not have antibodies that react with coronavirus antigenic polypeptides of the vaccine, or may have preexisting antibodies to coronavirus (e.g., SARS-CoV- 2) antigenic polypeptides of the vaccine because they have previously had an infection with the coronavirus or may have previously been administered a dose of a vaccine (e.g., an mRNA vaccine) that induces antibodies against the coronavirus.

Antigens

Antigens are proteins that induce an immune response (e.g., causing an immune system to produce antibodies against the antigens). Herein, use of the term “antigen” encompasses antigenic/immunogenic proteins and antigenic/immunogenic fragments (an immunogenic fragment that induces (or is capable of inducing) an immune response to a (at least one) coronavirus), unless otherwise stated. Likewise, the term “protein” encompasses peptides. Other molecules may be antigenic such as bacterial polysaccharides or combinations of protein and polysaccharide structures, such as viral membrane glycoproteins, but for the viral vaccines included herein, viral proteins, fragments of viral proteins, viral membrane glycoprotein and designed and or mutated proteins and glycoprotein derived from SARS-CoV-2 are the antigens provided herein.

Exemplary sequences of the coronavirus antigens and the mRNA encoding the coronavirus antigens of the present disclosure are provided in Table 1.

In some embodiments, an mRNA encodes a coronavirus spike protein antigen of SARS- CoV-2, SARS-CoV, MERS-CoV, HKUl-CoV, M-CoV, or NL63-CoV.

SARS-CoV, for severe acute respiratory distress syndrome (SARS), is a betacoronavirus that infects the human respiratory tract. Symptoms of SARS-CoV infection can range from mild, such as those similar to a common cold (nasal discharge, sore throat, low fever), to severe, including acute respiratory distress syndrome, which may be fatal. See, e.g. Nat Rev Microbiol. 2009. 7(3):226-236. An example of an RNA sequence encoding a SARS-CoV S protein is given by SEQ ID NO: 16. An example of an amino acid sequence of a SARS-CoV S protein is given by SEQ ID NO: 17.

MERS-CoV, for Middle East Respiratory Syndrome (MERS), is a betacoronavirus that infects the human respiratory tract. Symptoms of MERS-CoV infection can range from mild, such as those similar to a common cold (nasal discharge, sore throat, low fever), to severe, including acute respiratory distress syndrome, which may be fatal. MERS-CoV is endemic in dromedary camels of East Africa and the Arabian Peninsula, and was first reported to infect humans in 2012. Though zoonotic in origin, human-to-human transmission is possible. See, e.g., Ramadan et al. Germs. 2019. 9(l):35-42. An example of an RNA sequence encoding a MERS- CoV S protein is given by SEQ ID NO: 18. An example of an amino acid sequence of a MERS- CoV S protein is given by SEQ ID NO: 19.

M-CoV is a betacoronavirus that infects mice, with the mouse hepatitis virus (MHV or MHV-CoV) strain being commonly used in mouse models of coronavirus infection. MHV primarily infects the upper respiratory tract of mice, reproducing much of the pathogenesis of human coronaviruses. See, e.g., Korner et al. Viruses. 2020. 12(8):880. An example of an RNA sequence encoding an M-CoV S protein is given by SEQ ID NO: 20. An example of an amino acid sequence of an M-CoV S protein is given by SEQ ID NO: 21.

HKUl-CoV is a betacoronavirus that infects the human respiratory tract, causing symptoms of the common cold, with the potential to progress to more severe pneumonia and/or bronchitis. HKUl-CoV likely originated from spillover of a rodent betacoronavirus into humans, but is now endemic in origin. See, e.g., Lau et al. J Clin Microbiol. 2006. 44(6):2063-2071. An example of an RNA sequence encoding an HKUl-CoV S protein is given by SEQ ID NO: 22.

An example of an amino acid sequence of an HKUl-CoV S protein is given by SEQ ID NO: 23.

NL63-CoV is an alpha that infects the human respiratory tract, particularly of children. Infection by NL63-CoV typically causes upper respiratory tract symptoms similar to the common cold, but may progress to more severe symptoms of pneumonia or bronchitis following infection of the lower respiratory tract. See, e.g., Abdul-Rasool et al. Open Virol J. 2010. 4:76-84. An example of an RNA sequence encoding an NL63-CoV S protein is given by SEQ ID NO: 24. An example of an amino acid sequence of an NL63-CoV S protein is given by SEQ ID NO: 25.

In some embodiments, an mRNA encodes a coronavirus antigen that comprises an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or up to 100% identity to the amino acid sequence of SEQ ID NOs: 15, 17, 19, 21, 23, or 25, wherein the variation is in any amino acid sequence along the full length of the amino acid sequence, wherein the crown of a helix turn region comprises at least two amino acid residues comprising either inserted glycine or proline residues or amino acid residues mutated/substituted to either glycine and/or proline or a combination thereof. In some embodiments, the crown of the helix turn region comprises at least three glycine residues and/or proline residues wherein the glycine and/or proline residues result from modifications of the wild type sequences. In some embodiments, the crown of the helix turn region comprises at least four glycines and/or prolines.

Any one of the antigens encoded by the mRNA described herein may or may not comprise a signal sequence or other trafficking sequence/signal.

Nucleic Acids

The RNA of the present disclosure comprises an open reading frame (ORF) encoding a coronavirus antigen. In some embodiments, the RNA is a messenger RNA (mRNA). In some embodiments, the RNA (e.g., mRNA) further comprises a 5' untranslated region (UTR), 3' UTR, a poly (A) tail and/or a 5' cap analog. It should also be understood that the coronavirus vaccine of the present disclosure may include any 5' UTR and/or any 3' UTR. Exemplary UTR sequences are provided in the Sequence Listing ( e.g ., SEQ ID NOs: 2, 12, 4, and 13); however, other UTR sequences may be used or exchanged for any of the UTR sequences described herein. UTRs may also be omitted from the RNAs provided herein.

Nucleic acids comprise a polymer of nucleotides (nucleotide monomers). Thus, nucleic acids are also referred to as polynucleotides. Nucleic acids may be or may include, for example, deoxyribonucleic acids (DNAs), ribonucleic acids (RNAs), threose nucleic acids (TNAs), glycol nucleic acids (GNAs), peptide nucleic acids (PNAs), locked nucleic acids (LNAs, including LNA having a b-D-ribo configuration, a-LNA having an a-L-ribo configuration (a diastereomer of LNA), 2'-amino-LNA having a 2'-amino functionalization, and 2'-amino- a-LNA having a 2'- amino functionalization), ethylene nucleic acids (ENA), cyclohexenyl nucleic acids (CeNA) and/or chimeras and/or combinations thereof.

Messenger RNA (mRNA) includes RNA that encodes a (at least one) protein (a naturally occurring, non-naturally occurring, or modified polymer of amino acids) and can be translated to produce the encoded protein in vitro , in vivo , in situ , or ex vivo. The skilled artisan will appreciate that, except where otherwise noted, nucleic acid sequences set forth in the instant application may recite “T”s in a representative DNA sequence but where the sequence represents RNA (e.g., mRNA), the “T”s would be substituted for “U”s. Thus, any of the DNAs disclosed and identified by a particular sequence identification number herein also disclose the corresponding RNA (e.g. , mRNA) sequence complementary to the DNA, where each “T” of the DNA sequence is substituted with “U” (e.g., chemically modified or not chemically modified).

An open reading frame (ORF) is a continuous stretch of DNA or RNA beginning with a start codon (e.g., methionine (ATG or AUG)) and ending with a stop codon (e.g., TAA, TAG or TGA, or UAA, UAG or UGA). An ORF typically encodes a protein. The sequences disclosed herein may further comprise additional elements, e.g., 5' and 3' UTRs, but those elements, unlike the ORF, need not necessarily be present in an RNA of the present disclosure.

In some embodiments, an mRNA comprises a nucleotide sequence having at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or 100% identity to the nucleotide sequence of SEQ ID NO: 1 or 6. In some embodiments, an mRNA that comprises the nucleotide sequence of SEQ ID NO: 1. In some embodiments, an mRNA that comprises the nucleotide sequence of SEQ ID NO: 6.

In some embodiments, an mRNA that comprises an open reading frame (ORF) that comprises a nucleotide sequence having at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or 100% identity to the nucleotide sequence of SEQ ID NO: 3 or 7. In some embodiments, an mRNA that comprises an ORF that comprises the nucleotide sequence of SEQ ID NO: 3. In some embodiments, an mRNA that comprises an ORF that comprises the nucleotide sequence of SEQ ID NO: 7.

In some embodiments, an mRNA that comprises an open reading frame (ORF) that comprises a nucleotide sequence having at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or 100% identity to the nucleotide sequence of SEQ ID NO: 16, 18, 20, 22, or 24. In some embodiments, an mRNA that comprises an ORF that comprises the nucleotide sequence of SEQ ID NO: 16. In some embodiments, an mRNA that comprises an ORF that comprises the nucleotide sequence of SEQ ID NO: 18. In some embodiments, an mRNA that comprises an ORF that comprises the nucleotide sequence of SEQ ID NO: 20. In some embodiments, an mRNA that comprises an ORF that comprises the nucleotide sequence of SEQ ID NO: 22. In some embodiments, an mRNA that comprises an ORF that comprises the nucleotide sequence of SEQ ID NO: 24.

Modified protein

In some embodiments, an mRNA encodes a coronavirus antigen or modified coronavirus protein or glycoprotein. Antigens or other polypeptides that are modified proteins are molecules that differ in their amino acid sequence from a wild-type, native, or reference sequence (also referred to herein as a parent sequence). The antigen/polypeptide may possess substitutions, deletions, and/or insertions at certain positions within the amino acid sequence, as compared to a native or reference sequence. Ordinarily, modified proteins possess at least 50% identity to a wild-type, native or reference sequence. In some embodiments, modified proteins share at least 80%, or at least 90% identity with a wild-type, native, or reference sequence.

Antigens, such as proteins or glycoproteins encoded by nucleic acids of the disclosure may contain amino acid changes that confer any of a number of desirable properties, e.g., that enhance their immunogenicity, enhance their expression, and/or improve their stability or PK/PD properties in a subject. Antigens, such as proteins or glycoproteins can be made using routine mutagenesis techniques and assayed as appropriate to determine whether they possess the desired property. Assays to determine expression levels and immunogenicity are well known in the art and exemplary such assays are set forth in the Examples section. Similarly, PK/PD properties of a protein can be measured using art recognized techniques, e.g., by determining expression of antigens in a vaccinated subject over time and/or by looking at the durability of the induced immune response. The stability of protein(s) encoded by a nucleic acid may be measured by assaying thermal stability or stability upon urea denaturation or may be measured using in silico prediction. Methods for such experiments and in silico determinations are known in the art. In some embodiments, an mRNA or an mRNA ORF comprises a nucleotide sequence of any one of the sequences provided herein (see, e.g., Sequence Listing and Table 1), or comprises a nucleotide sequence at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to a nucleotide sequence of any one of the sequences provided herein. In some embodiments, an mRNA or an mRNA ORF comprises a nucleotide sequence that is less than 100% identical to a nucleotide sequence of SEQ ID NO: 16 or SEQ ID NO: 3. In some embodiments, an mRNA or an mRNA ORF comprises a nucleotide sequence encoding an amino acid comprising at least two glycine mutations (e.g., glycine substitutions) relative to the amino acid encoded by SEQ ID NO: 16 or SEQ ID NO: 3.

In some embodiments, an mRNA or an mRNA ORF encodes a protein of any one of the sequences provided herein (see, e.g., Sequence Listing and Table 1), or encodes an amino acid sequence at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to an amino acid sequence of any one of the sequences provided herein. In some embodiments, an mRNA or an mRNA ORF encodes an amino acid sequence that is less than 100% identical to an amino acid sequence of SEQ ID NO: 15 or SEQ ID NO: 5. In some embodiments, an mRNA or an mRNA ORF comprises a nucleotide sequence encoding an amino acid comprising at least two glycine mutations (e.g., glycine substitutions) relative to the amino acid sequences SEQ ID NO: 15 or SEQ ID NO: 5.

The present disclosure provides, in some aspects, an mRNA comprising an ORF that encodes a coronavims membrane-bound spike (S) protein antigen, wherein the S protein antigen comprises a crown of a helix turn region of the S protein having at least two mutations relative to a crown of a helix turn region of a wild-type coronavims spike protein, wherein one of the mutations is a glycine mutation. Coronavimses of the family Coronaviridae are named for the crown of the club-shaped spike proteins that cover the surface of viral particles. In this case, the spike protein is a glycoprotein. Each spike typically comprises a trimer of three full-length S protein monomers. Each monomer comprises an amino acid sequence with two subunits, SI and S2. The SI subunit comprises an N-terminal domain (NTD), receptor-binding domain (RBD) and receptor-binding motif (RBM). The S2 subunit comprises a fusion peptide (FP), central helix (CH), heptad repeat 1 (HR1), heptad repeat 2 (HR2), transmembrane (TM) domain, and cytoplasmic domain.

A helix turn region, or “helix-turn-helix” region, of a protein is a region or domain of a protein characterized by two alpha helices that are connected by a short amino acid stretch often containing turn sequences changing the direction of the protein. A crown of a helix turn region or helix-turn-helix region refers to the amino acid sequence connecting the alpha helices. The terminal amino acids of the crown may overlap with either of the helices connected by the crown, and belong to both an alpha helix and crown. The crown of a helix turn region may vary in length, but generally comprises about 10 to about 15 amino acids. A mutation may be a substitution, in which one amino acid is substituted for another, with a glycine substitution being a substitution in which a non-glycine amino acid is substituted for a glycine or a non-proline amino acid is substituted for a proline. A mutation may be an insertion, in which an amino acid sequence comprising a mutation comprises one or more additional glycines and/or prolines relative to a wild-type amino acid sequence that is not mutated.

Coronavims S protein modified proteins encoded by mRNAs of the present disclosure comprise at least two amino acid substitutions, relative to a wild-type coronavims S protein, in a crown of a helix turn region, with at least one amino acid substitution being a glycine and/or proline substitution. The crown of the helix turn region of coronavims S proteins plays an important role in stabilizing the conformation of the S protein trimer by facilitating hydrogen bonding between amino acids of the SI and S2 subunits. For example, the amino acids corresponding to positions L984, D985, K986, and V987 of the S protein of the SARS-CoV-2 USA-WA1/2020 isolate (e.g., SEQ ID NO: 15) are located in the crown of a helix turn region bridging the HR1 and CH of the S2 subunit. These amino acids, as well as others of the crown, hydrogen bond with amino acids of the S 1 subunit, stabilizing the conformation of the S protein trimer. Substitution of one or more of these amino acids dismpts the formation of stabilizing hydrogen bonds with the S 1 subunit, thereby increasing the flexibility of the S protein trimer. Substitutions with glycine and/or proline have a particularly strong effect on flexibility. The R- group of glycine comprises only a single hydrogen atom, making glycine’s R- group the smallest among the canonical amino acids. The small R-group of glycine limits the possibility of steric hindrance with other amino acids in a protein structure, and thus glycine substitutions increase the rotational flexibility of an amino acid sequence in a protein. When present in a polypeptide or protein, the nitrogen of proline is bound only to carbon atoms, and with no bound hydrogen, it cannot act as a hydrogen bond acceptor or form hydrogen bonds. This inability to hydrogen bond inhibits alpha helix formation, and so proline substitutions also increase the flexibility of an amino acid sequence in a protein.

In some embodiments, an mRNA encodes a SARS-CoV-2 or other CoV S protein comprising a crown of a helix turn region that has an increased helix flexibility relative to a crown of a helix turn region of a 2P-stabilized prefusion coronavims S protein. A 2P-stabilized coronavims S protein is an S protein with two proline substitutions that stabilize the S protein in a prefusion conformation. An exemplary 2P-stabilized coronavims S protein is provided in SEQ ID NO: 5, which comprises the amino acid sequence of the S protein of SARS-CoV-2 Wuhan- Hu-1 isolate (USA-WA1/2020 isolate) (SEQ ID NO: 15), and two proline substitutions at the positions corresponding to K986 and V987 (K986P and V987P substitutions). Coronavims S proteins undergo a conformational change during fusion, when the viral envelope fuses with a target cell membrane. Prior to fusion, the prefusion conformation of the S protein extends outward from the viral envelope in a linear conformation. During fusion, the S protein jackknifes, folding in on itself to bring the viral envelope closer to the cell membrane and facilitate merging of the envelope and cell membrane (see, e.g., Cai et al. Science. 2020.

369(6511): 1586-1592). A 2P- stabilized S protein is less able to jackknife in this manner, and thus more likely to remain in the prefusion conformation. Helix flexibility refers to the ability of a protein or protein domain to achieve different conformations, such as through rotation or bending of alpha helices or linker sequences. A more flexible protein or protein domain being able to achieve more conformations than a less flexible (more rigid) protein or protein domain. Methods of measuring helix flexibility are well known in the art (see, e.g., Kumeta et al. J Cell Sci. 2018. 131(l):jcs206326).

In some embodiments, the crown of the helix turn region comprises at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 glycines and/or prolines. In some embodiments, the crown of the helix turn region comprises 2 glycines and/or prolines. In some embodiments, the crown of the helix turn region comprises 3 glycines and/or prolines. In some embodiments, the crown of the helix turn region comprises 4 glycines and/or prolines. In some embodiments, the mRNA comprises an ORF that encodes a coronavims S protein antigen having at least 80% identity to the amino acid sequence of SEQ ID NO: 5, wherein the spike protein antigen comprises a crown of a helix turn region having at least two glycines. In some embodiments, the mRNA comprises an ORF that encodes a coronavims S protein antigen having at least 80% identity to the amino acid sequence of SEQ ID NO: 5, wherein the spike protein antigen comprises a crown of a helix turn region having at least two glycines. In some embodiments, the crown of the helix turn region comprises at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 glycines. In some embodiments, the crown of the helix turn region comprises 2 glycines. In some embodiments, the crown of the helix turn region comprises 3 glycines. In some embodiments, the crown of the helix turn region comprises 4 glycines.

In some embodiments, an mRNA comprises an ORF that encodes a coronavims S protein antigen comprising a helix turn region and a transmembrane region, wherein the S protein antigen comprises at least two glycines within a crown of the helix turn region of the S protein.

In some embodiments, the crown of the helix turn region comprises at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 glycines and/or prolines. In some embodiments, the crown of the helix turn region comprises 2 glycines. In some embodiments, the crown of the helix turn region comprises 3 glycines and/or prolines. In some embodiments, the crown of the helix turn region comprises 4 glycines and/or prolines.

In some embodiments, a coronavirus S protein encoded by an mRNA provided herein comprises a crown of a helix turn region comprising about 10, about 11, about 12, about 13, about 14, or about 15 amino acids. In some embodiments, the crown of the helix turn region comprises about 12 amino acids. In some embodiments, the crown of the helix turn region comprises about 12 amino acids in the S2 subunit between the heptad repeat 1 (HR1) and central helix (CH). In some embodiments, the crown of the helix turn region comprises about 12 amino acids in the S2 subunit between the heptad repeat 1 (HR1) and heptad repeat 2 (HR2). In some embodiments, the crown of the helix turn region comprises at least 4 glycines and/or prolines. In some embodiments, the crown of the helix turn region comprises at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 glycines and/or prolines.

In some embodiments, an mRNA encodes a SARS-CoV-2 or other CoV S modified protein. A SARS-CoV-2 or other CoV S modified protein may comprise, for example, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 amino acid substitutions relative to the amino acid sequence of a wild- type SARS-CoV-2. A wild-type coronavirus S protein is a coronavirus S protein comprising an amino acid sequence found in a coronavirus isolate, such as a coronavirus obtained from a vertebrate host. An example of a wild-type coronavirus S protein is the S protein of the SARS- CoV-2 USA-WA1/2020 isolate, which has the amino acid sequence of SEQ ID NO: 15. In some embodiments, the crown of a helix turn region comprises at least two amino acid substitutions (e.g., at least 2, 3, 4, 5, 6, 7, 8 , 9, or 10 amino acid substitutions), and at least one amino acid substitution is a glycine substitution. In some embodiments, the crown of the helix turn region comprises at least two glycine substitutions. In some embodiments, the crown of the helix turn region comprises at least three glycine substitutions. In some embodiments, the crown of the helix turn region comprises at least four glycine substitutions.

The amino acid substitutions, in some embodiments, are at any one or more of positions L984, D985, K986, and V987 relative to the amino acid sequence of SEQ ID NO: 15. In some embodiments, the SARS-CoV-2 S protein comprises at least two glycine substitutions at positions selected from the group consisting of L984, D985, K986, and V987 relative to the amino acid sequence of SEQ ID NO: 15. In some embodiments, the SARS-CoV-2 S protein comprises four glycine substitutions at positions selected from the group consisting of L984, D985, K986, and V987 relative to the amino acid sequence of SEQ ID NO: 15 (e.g. the mRNA encodes a SARS-CoV-2 S modified protein in which amino acids 984-987 relative to SEQ ID NO: 15 comprise the amino acid sequence GGGG (SEQ ID NO: 11). A mutation may be an insertion, in which an amino acid sequence comprising a mutation comprises one or more additional amino acids relative to a wild-type amino acid sequence that is not mutated. A glycine insertion is a mutation in which one or more glycines are added to an amino acid sequence. In some embodiments, an mRNA encodes a SARS-CoV-2 or other coronavirus S modified protein comprising an amino acid insertion in the crown of a helix turn region of the S protein. In some embodiments, the insertion comprises 2-10 glycines and/or prolines. In some embodiments, the insertion comprises 2, 3, 4, 5, 6, 7, 8, 9, or 10 glycines. In some embodiments, the insertion comprises 2, 3, 4, 5, 6, 7, 8, 9, or 10 prolines. In some embodiments, the insertion comprises 2, 3, 4, 5, 6, 7, 8, 9, or 10 amino acids, wherein each amino acid of the insertion is a glycine or proline.

In some embodiments, the mRNA encodes a SARS-CoV-2 or other coronavirus S modified protein comprising a crown of a helix turn region, wherein the crown comprises at least four (e.g., at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15) glycines. In some embodiments, the crown of the helix turn region comprises 4-10 glycines. In some embodiments, the crown of the helix turn region comprises 4-10 prolines. In some embodiments, the crown of the helix turn region comprises 4-10 glycines and/or prolines (i.e., the sum of the number of glyines and the number of prolines in the crown of the helix turn region is at least 4 but not more than 10). An mRNA may encode a SARS-CoV-2 or other coronavirus S modified protein comprising a crown of a helix turn region containing the requisite number of prolines and/or glycines due to substitution mutations, insertion mutations, or a combination of both. In some embodiments, the glycines of the crown of the helix turn region are amino acid substitutions relative to a wild-type coronavirus spike protein. In some embodiments, the mRNA encodes a SARS-CoV-2 S modified protein having at least 80%, at least 85%, at least 90%, at least 95%, or at least 98% identity to the amino acid sequence of SEQ ID NO: 8 In some embodiments, the mRNA encodes a SARS-CoV-2 S modified protein having at least 95% identity to the amino acid sequence of SEQ ID NO: 8. In some embodiments, the mRNA encodes a SARS-CoV-2 S modified protein comprising the amino acid sequence of SEQ ID NO: 8.

In some embodiments, the mRNA comprises an ORF having at least 80%, at least 85%, at least 90%, at least 95%, or at least 98% identity to the nucleotide sequence of SEQ ID NO: 7 In some embodiments, the mRNA comprises an ORF having at least 95% identity to the nucleotide sequence of SEQ ID NO: 7. In some embodiments, the ORF comprises nucleotide sequence of SEQ ID NO: 7.

The term “identity” refers to a relationship between the sequences of two or more polypeptides (e.g. protein antigens) or polynucleotides (nucleic acids), as determined by comparing the sequences. Identity also refers to the degree of sequence relatedness between or among sequences as determined by the number of matches between strings of two or more amino acid residues or nucleic acid residues. Identity measures the percent of identical matches between the smaller of two or more sequences with gap alignments (if any) addressed by a particular mathematical model or computer program ( e.g ., “algorithms”). Identity of related antigens or nucleic acids can be readily calculated by known methods. “Percent (%) identity” as it applies to polypeptide or polynucleotide sequences is defined as the percentage of residues (amino acid residues or nucleic acid residues) in the candidate amino acid or nucleic acid sequence that are identical with the residues in the amino acid sequence or nucleic acid sequence of a second sequence after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent identity. Methods and computer programs for the alignment are well known in the art. It is understood that identity depends on a calculation of percent identity but may differ in value due to gaps and penalties introduced in the calculation. Generally, modified protein of a particular polynucleotide or polypeptide (e.g., antigen) have at least 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% but less than 100% sequence identity to that particular reference polynucleotide or polypeptide as determined by sequence alignment programs and parameters described herein and known to those skilled in the art. Such tools for alignment include those of the BLAST suite (Stephen F. Altschul, et al (1997), "Gapped BLAST and PSI-BLAST: a new generation of protein database search programs", Nucleic Acids Res. 25:3389-3402). Another local alignment technique is based on the Smith- Waterman algorithm (Smith, T.F. & Waterman, M.S. (1981) “Identification of common molecular subsequences.” J. Mol. Biol. 147:195-197). A general global alignment technique based on dynamic programming is the Needleman-Wunsch algorithm (Needleman, S.B. & Wunsch, C.D. (1970) “A general method applicable to the search for similarities in the amino acid sequences of two proteins.” J. Mol. Biol. 48:443-453). A Fast Optimal Global Sequence Alignment Algorithm (FOGSAA) has also been developed that purportedly produces global alignment of nucleotide and protein sequences faster than other optimal global alignment methods, including the Needleman-Wunsch algorithm.

As such, polynucleotides encoding peptides or polypeptides containing substitutions, insertions and/or additions, deletions and covalent modifications with respect to reference sequences, in particular the protein (e.g., antigen) sequences disclosed herein, are included within the scope of this disclosure. For example, sequence tags or amino acids, such as one or more lysines, can be added to peptide sequences (e.g., at the N-terminal or C-terminal ends). Sequence tags can be used for peptide detection, purification or localization. Lysines can be used to increase peptide solubility or to allow for biotinylation. Alternatively, amino acid residues located at the carboxy and amino terminal regions of the amino acid sequence of a protein may optionally be deleted providing for truncated sequences. Certain amino acids ( e.g ., C-terminal or N-terminal residues) may alternatively be deleted depending on the use of the sequence, as for example, expression of the sequence as part of a larger sequence which is soluble or linked to a solid support. In some embodiments, sequences for (or encoding) signal sequences, termination sequences, transmembrane domains, linkers, multimerization domains (such as, e.g., foldon regions) and the like may be substituted with alternative sequences that achieve the same or a similar function. In some embodiments, cavities in the core of proteins can be filled to improve stability, e.g., by introducing larger amino acids. In other embodiments, buried hydrogen bond networks may be replaced with hydrophobic resides to improve stability. In yet other embodiments, glycosylation sites may be removed and replaced with appropriate residues. Such sequences are readily identifiable to one of skill in the art. It should also be understood that some of the sequences provided herein contain sequence tags or terminal peptide sequences (e.g., at the N-terminal or C-terminal ends) that may be deleted, for example, prior to use in the preparation of an RNA (e.g., mRNA) vaccine.

As recognized by those skilled in the art, protein fragments, functional protein domains, and homologous proteins are also considered to be within the scope of coronavims antigens of interest. For example, provided herein is any protein fragment (meaning a protein sequence at least one amino acid residue shorter than a reference antigen sequence but otherwise identical) of a reference protein, provided that the fragment is immunogenic and confers a protective immune response to the coronavims. In addition to modified protein that are identical to the reference protein but are truncated, in some embodiments, an antigen includes 2, 3, 4, 5, 6, 7, 8, 9, 10, or more mutations, as shown in any of the sequences provided or referenced herein. Antigens can range in length from about 4, 6, or 8 amino acids to full length proteins.

Stabilizing Elements

Naturally-occurring eukaryotic mRNA molecules can contain stabilizing elements, including, but not limited to untranslated regions (UTR) at their 5 '-end (5' UTR) and/or at their 3'-end (3' UTR), in addition to other structural features, such as a 5'-cap structure or a 3'-poly(A) tail. Both the 5' UTR and the 3' UTR are typically transcribed from the genomic DNA and are elements of the premature mRNA. Characteristic structural features of mature mRNA, such as the 5 '-cap and the 3 '-poly (A) tail are usually added to the transcribed (premature) mRNA during mRNA processing.

In some embodiments, an RNA has an open reading frame encoding at least one antigen having at least one modification, at least one 5' terminal cap, and is formulated within a lipid nanoparticle. 5 '-capping of polynucleotides may be completed concomitantly during the in vitro- transcription reaction using the following chemical RNA cap analogs to generate the 5'- guanosine cap structure according to manufacturer protocols: 3'-0-Me-m7G(5')ppp(5') G [the ARCA cap];G(5')ppp(5')A; G(5')ppp(5')G; m7G(5')ppp(5')A; m7G(5')ppp(5')G (New England BioLabs, Ipswich, MA). 5'-capping of modified RNA may be completed post-transcriptionally using a Vaccinia Virus Capping Enzyme to generate the “Cap 0” structure: m7G(5')ppp(5')G (New England BioLabs, Ipswich, MA). Cap 1 structure may be generated using both Vaccinia Virus Capping Enzyme and a 2'-0 methyl-transferase to generate: m7G(5')ppp(5')G-2'-0- methyl. Cap 2 structure may be generated from the Cap 1 structure followed by the 2'-0- methylation of the 5 '-antepenultimate nucleotide using a 2'-0 methyl-transferase. Cap 3 structure may be generated from the Cap 2 structure followed by the 2'-0-methylation of the 5'- preantepenultimate nucleotide using a 2'-0 methyl-transferase. Enzymes may be derived from a recombinant source.

The 3'-poly(A) tail is typically a stretch of adenine nucleotides added to the 3 '-end of the transcribed mRNA. It can, in some instances, comprise up to about 400 adenine nucleotides. In some embodiments, the length of the 3'-poly(A) tail may be an essential element with respect to the stability of the individual mRNA.

In some embodiments, an RNA includes a stabilizing element. Stabilizing elements may include for instance a histone stem-loop. A stem-loop binding protein (SLBP), a 32 kDa protein has been identified. It is associated with the histone stem-loop at the 3'-end of the histone messages in both the nucleus and the cytoplasm. Its expression level is regulated by the cell cycle; it peaks during the S-phase, when histone mRNA levels are also elevated. The protein has been shown to be essential for efficient 3'-end processing of histone pre-mRNA by the U7 snRNP. SLBP continues to be associated with the stem-loop after processing, and then stimulates the translation of mature histone mRNAs into histone proteins in the cytoplasm. The RNA binding domain of SLBP is conserved through metazoa and protozoa; its binding to the histone stem- loop depends on the structure of the loop. The minimum binding site includes at least three nucleotides 5’ and two nucleotides 3' relative to the stem- loop.

In some embodiments, an RNA (e.g., mRNA) includes a coding region, at least one histone stem-loop, and optionally, a poly(A) sequence or polyadenylation signal. The poly(A) sequence or polyadenylation signal generally should enhance the expression level of the encoded protein. The encoded protein, in some embodiments, is not a histone protein, a reporter protein (e.g. Luciferase, GFP, EGFP, b-Galactosidase, EGFP), or a marker or selection protein (e.g. alpha-Globin, Galactokinase and Xanthine:guanine phosphoribosyl transferase (GPT)).

In some embodiments, an RNA (e.g., mRNA) includes the combination of a poly(A) sequence or polyadenylation signal and at least one histone stem-loop, even though both represent alternative mechanisms in nature, acts synergistically to increase the protein expression beyond the level observed with either of the individual elements. The synergistic effect of the combination of poly(A) and at least one histone stem-loop does not depend on the order of the elements or the length of the poly(A) sequence.

In some embodiments, an RNA ( e.g ., mRNA) does not include a histone downstream element (HDE). “Histone downstream element” (HDE) includes a purine-rich polynucleotide stretch of approximately 15 to 20 nucleotides 3' of naturally occurring stem- loops, representing the binding site for the U7 snRNA, which is involved in processing of histone pre-mRNA into mature histone mRNA. In some embodiments, the nucleic acid does not include an intron.

An RNA (e.g., mRNA) may or may not contain an enhancer and/or promoter sequence, which may be modified or unmodified or which may be activated or inactivated. In some embodiments, the histone stem-loop is generally derived from histone genes and includes an intramolecular base pairing of two neighbored partially or entirely reverse complementary sequences separated by a spacer, consisting of a short sequence, which forms the loop of the structure. The unpaired loop region is typically unable to base pair with either of the stem loop elements. It occurs more often in RNA, as is a key component of many RNA secondary structures but may be present in single- stranded DNA as well. Stability of the stem-loop structure generally depends on the length, number of mismatches or bulges, and base composition of the paired region. In some embodiments, wobble base pairing (non-Watson-Crick base pairing) may result. In some embodiments, the at least one histone stem-loop sequence comprises a length of 15 to 45 nucleotides.

In some embodiments, an RNA (e.g., mRNA) has one or more AU-rich sequences removed. These sequences, sometimes referred to as AURES are destabilizing sequences found in the 3’UTR. The AURES may be removed from the RNA vaccines. Alternatively, the AURES may remain in the RNA vaccine.

Signal Peptides

In some embodiments, an RNA (e.g., mRNA) having an ORF that encodes a signal peptide fused to the coronavirus antigen. Signal peptides, comprising the N-terminal 15-60 amino acids of proteins, are typically needed for the translocation across the membrane on the secretory pathway and, thus, universally control the entry of most proteins both in eukaryotes and prokaryotes to the secretory pathway. In eukaryotes, the signal peptide of a nascent precursor protein (pre-protein) directs the ribosome to the rough endoplasmic reticulum (ER) membrane and initiates the transport of the growing peptide chain across it for processing. ER processing produces mature proteins, wherein the signal peptide is cleaved from precursor proteins, typically by a ER-resident signal peptidase of the host cell, or they remain uncleaved and function as a membrane anchor. A signal peptide may also facilitate the targeting of the protein to the cell membrane.

A signal peptide may have a length of 15-60 amino acids. For example, a signal peptide may have a length of 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or

60 amino acids. In some embodiments, a signal peptide has a length of 20-60, 25-60, 30-60, 35- 60, 40-60, 45- 60, 50-60, 55-60, 15-55, 20-55, 25-55, 30-55, 35-55, 40-55, 45-55, 50-55, 15-50, 20-50, 25-50, 30-50, 35-50, 40-50, 45-50, 15-45, 20-45, 25-45, 30-45, 35-45, 40-45, 15-40, 20- 40, 25-40, 30-40, 35-40, 15-35, 20-35, 25-35, 30-35, 15-30, 20-30, 25-30, 15-25, 20-25, or 15-20 amino acids.

Signal peptides from heterologous genes (which regulate expression of genes other than coronavirus antigens in nature) are known in the art and can be tested for desired properties and then incorporated into a nucleic acid of the disclosure. In some embodiments, the signal peptide may comprise one of the following sequences: MDSKGSSQKGSRLLLLLVVSNLLLPQGVVG (SEQ ID NO: 26), MD WTWILFL V A A ATRVHS (SEQ ID NO: 27);

METPAQLLFLLLLWLPDTTG (SEQ ID NO: 28); MLGS N S GQR V VFTILLLL V AP A Y S (SEQ ID NO: 29); MKCLLYLAFLFIGVNCA (SEQ ID NO: 30); MWL V S LAIVT AC AG A (SEQ ID NO: 31); or MFVFL VLLPLV S S QC (SEQ ID NO: 32).

Fusion Proteins

In some embodiments, an RNA (e.g., mRNA) encodes an antigenic fusion protein. Thus, the encoded antigen or antigens may include two or more proteins (e.g., protein and/or protein fragment) joined together. Alternatively, the protein to which a protein antigen is fused does not promote a strong immune response to itself, but rather to the coronavirus antigen. Antigenic fusion proteins, in some embodiments, retain the functional property from each original protein.

Scaffold Moieties

The RNA ( e.g ., mRNA) vaccines as provided herein, in some embodiments, encode fusion proteins that comprise coronavirus antigens linked to scaffold moieties. In some embodiments, such scaffold moieties impart desired properties to an antigen encoded by a nucleic acid of the disclosure. For example, scaffold proteins may improve the immunogenicity of an antigen, e.g., by altering the structure of the antigen, altering the uptake and processing of the antigen, and/or causing the antigen to bind to a binding partner.

In some embodiments, the scaffold moiety is protein that can self-assemble into protein nanoparticles that are highly symmetric, stable, and structurally organized, with diameters of 10- 150 nm, a highly suitable size range for optimal interactions with various cells of the immune system. In some embodiments, viral proteins or virus-like particles can be used to form stable nanoparticle structures. Examples of such viral proteins are known in the art. For example, in some embodiments, the scaffold moiety is a hepatitis B surface antigen (HBsAg). HBsAg forms spherical particles with an average diameter of ~22 nm and which lacked nucleic acid and hence are non-inf ectious (Lopez-Sagaseta, J. et al. Computational and Structural Biotechnology Journal 14 (2016) 58-68). In some embodiments, the scaffold moiety is a hepatitis B core antigen (HBcAg) self-assembles into particles of 24-31 nm diameter, which resembled the viral cores obtained from HBV-infected human liver. HBcAg produced in self-assembles into two classes of differently sized nanoparticles of 300 A and 360 A diameter, corresponding to 180 or 240 protomers. In some embodiments, the coronavirus antigen is fused to HBsAG or HBcAG to facilitate self-assembly of nanoparticles displaying the coronavirus antigen.

In some embodiments, bacterial protein platforms may be used. Non-limiting examples of these self-assembling proteins include ferritin, lumazine and encapsulin.

Ferritin is a protein whose main function is intracellular iron storage. Ferritin is made of 24 subunits, each composed of a four- alpha-helix bundle, that self-assemble in a quaternary structure with octahedral symmetry (Cho K.J. et al. J Mol Biol. 2009;390:83-98). Several high- resolution structures of ferritin have been determined, confirming that Helicobacter pylori ferritin is made of 24 identical protomers, whereas in animals, there are ferritin light and heavy chains that can assemble alone or combine with different ratios into particles of 24 subunits (Granier T. et al. J Biol Inorg Chem. 2003;8:105-111; Fawson D.M. et al. Nature. 1991; 349: 541-544). Ferritin self-assembles into nanoparticles with robust thermal and chemical stability. Thus, the ferritin nanoparticle is well-suited to carry and expose antigens.

Fumazine synthase (FS) is also well- suited as a nanoparticle platform for antigen display. FS, which is responsible for the penultimate catalytic step in the biosynthesis of riboflavin, is an enzyme present in a broad variety of organisms, including archaea, bacteria, fungi, plants, and eubacteria (Weber S.E. Flavins and Flavoproteins. Methods and Protocols, Series: Methods in Molecular Biology. 2014). The FS monomer is 150 amino acids long and consists of beta- sheets along with tandem alpha-helices flanking its sides. A number of different quaternary structures have been reported for FS, illustrating its morphological versatility: from homopentamers up to symmetrical assemblies of 12 pentamers forming capsids of 150 A diameter. Even FS cages of more than 100 subunits have been described (Zhang X. et al. J Mol Biol. 2006; 362: 753-770).

Encapsulin, a novel protein cage nanoparticle isolated from thermophile Thermotoga maritima, may also be used as a platform to present antigens on the surface of self-assembling nanoparticles. Encapsulin is assembled from 60 copies of identical 31 kDa monomers having a thin and icosahedral T = 1 symmetric cage structure with interior and exterior diameters of 20 and 24 nm, respectively (Sutter M. et al. Nat Struct Mol Biol. 2008, 15: 939-947). Although the exact function of encapsulin in T. maritima is not clearly understood yet, its crystal structure has been recently solved and its function was postulated as a cellular compartment that encapsulates proteins such as DyP (Dye decolorizing peroxidase) and Flp (Ferritin like protein), which are involved in oxidative stress responses (Rahmanpour R. et al. FEBS J. 2013, 280: 2097-2104).

In some embodiments, an RNA of the present disclosure encodes a coronavirus antigen (e.g., SARS-CoV-2 S protein) fused to a foldon domain. The foldon domain may be, for example, obtained from bacteriophage T4 fibritin (see, e.g., Tao Y, et al. Structure. 1997 Jun 15; 5(6):789-98).

Linkers and Cleavable Peptides

In some embodiments, the mRNAs of the disclosure encode more than one polypeptide, referred to herein as fusion proteins. In some embodiments, the mRNA further encodes a linker located between at least one or each domain of the fusion protein. The linker can be, for example, a cleavable linker or protease- sensitive linker. In some embodiments, the linker is selected from the group consisting of F2A linker, P2A linker, T2A linker, E2A linker, and combinations thereof. This family of self-cleaving peptide linkers, referred to as 2 A peptides, has been described in the art (see for example, Kim, J.H. et al. (2011) PLoS ONE 6:el8556). In some embodiments, the linker is an F2A linker. In some embodiments, the linker is a GGGS linker. In some embodiments, the fusion protein contains three domains with intervening linkers, having the structure: domain-linker-domain-linker-domain.

Cleavable linkers known in the art may be used in connection with the disclosure. Exemplary such linkers include: F2A linkers, T2A linkers, P2A linkers, E2A linkers (See, e.g., WO2017127750). The skilled artisan will appreciate that other art-recognized linkers may be suitable for use in the proteins of the disclosure (e.g., encoded by the nucleic acids of the disclosure). The skilled artisan will likewise appreciate that other polycistronic molecules (mRNA encoding more than one antigen/polypeptide separately within the same molecule) may be suitable for use as provided herein.

Sequence Optimization

In some embodiments, an ORF encoding an antigen of the disclosure is codon optimized. Codon optimization methods are known in the art. For example, an ORF of any one or more of the sequences provided herein may be codon optimized. Codon optimization, in some embodiments, may be used to match codon frequencies in target and host organisms to ensure proper folding; bias GC content to increase mRNA stability or reduce secondary structures; minimize tandem repeat codons or base runs that may impair gene construction or expression; customize transcriptional and translational control regions; insert or remove protein trafficking sequences; remove/add post translation modification sites in encoded protein ( e.g ., glycosylation sites); add, remove or shuffle protein domains; insert or delete restriction sites; modify ribosome binding sites and mRNA degradation sites; adjust translational rates to allow the various domains of the protein to fold properly; or reduce or eliminate problem secondary structures within the polynucleotide. Codon optimization tools, algorithms and services are known in the art - non limiting examples include services from GeneArt (Life Technologies), DNA2.0 (Menlo Park CA) and/or proprietary methods. In some embodiments, the open reading frame (ORF) sequence is optimized using optimization algorithms.

In some embodiments, a codon optimized sequence shares less than 95% sequence identity to a naturally-occurring or wild-type sequence ORF (e.g., a naturally-occurring or wild- type mRNA sequence encoding a coronavirus antigen). In some embodiments, a codon optimized sequence shares less than 90% sequence identity to a naturally-occurring or wild-type sequence (e.g., a naturally-occurring or wild-type mRNA sequence encoding a coronavirus antigen). In some embodiments, a codon optimized sequence shares less than 85% sequence identity to a naturally-occurring or wild-type sequence (e.g., a naturally-occurring or wild-type mRNA sequence encoding a coronavirus antigen). In some embodiments, a codon optimized sequence shares less than 80% sequence identity to a naturally-occurring or wild-type sequence (e.g., a naturally-occurring or wild-type mRNA sequence encoding a coronavirus antigen). In some embodiments, a codon optimized sequence shares less than 75% sequence identity to a naturally-occurring or wild-type sequence (e.g., a naturally-occurring or wild-type mRNA sequence encoding a coronavirus antigen).

In some embodiments, a codon optimized sequence shares between 65% and 85% (e.g., between about 67% and about 85% or between about 67% and about 80%) sequence identity to a naturally-occurring or wild-type sequence (e.g., a naturally-occurring or wild-type mRNA sequence encoding a coronavirus antigen). In some embodiments, a codon optimized sequence shares between 65% and 75% or about 80% sequence identity to a naturally-occurring or wild- type sequence (e.g., a naturally-occurring or wild-type mRNA sequence encoding a coronavirus antigen).

In some embodiments, a codon-optimized sequence encodes an antigen that is as immunogenic as, or more immunogenic than (e.g., at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 100%, or at least 200% more), than a coronavirus antigen encoded by a non-codon-optimized sequence.

When transfected into mammalian host cells, the modified mRNAs have a stability of between 12-18 hours, or greater than 18 hours, e.g., 24, 36, 48, 60, 72, or greater than 72 hours and are capable of being expressed by the mammalian host cells. In some embodiments, a codon optimized RNA may be one in which the levels of G/C are enhanced. The G/C-content of nucleic acid molecules ( e.g ., mRNA) may influence the stability of the RNA. RNA having an increased amount of guanine (G) and/or cytosine (C) residues may be functionally more stable than RNA containing a large amount of adenine (A) and thymine (T) or uracil (U) nucleotides. As an example, WO02/098443 discloses a pharmaceutical composition containing an mRNA stabilized by sequence modifications in the translated region. Due to the degeneracy of the genetic code, the modifications work by substituting existing codons for those that promote greater RNA stability without changing the resulting amino acid. The approach is limited to coding regions of the RNA.

Chemically Unmodified Nucleotides

In some embodiments, an RNA (e.g., mRNA) is not chemically modified and comprises the standard ribonucleotides consisting of adenosine, guanosine, cytosine and uridine. In some embodiments, nucleotides and nucleosides of the present disclosure comprise standard nucleoside residues such as those present in transcribed RNA (e.g. A, G, C, or U). In some embodiments, nucleotides and nucleosides of the present disclosure comprise standard deoxyribonucleosides such as those present in DNA (e.g. dA, dG, dC, or dT).

Chemical Modifications

The RNA of the present disclosure comprise, in some embodiments, has an open reading frame encoding a coronavirus antigen, wherein the nucleic acid comprises nucleotides and/or nucleosides that can be standard (unmodified) or modified as is known in the art. In some embodiments, nucleotides and nucleosides of the present disclosure comprise modified nucleotides or nucleosides. Such modified nucleotides and nucleosides can be naturally- occurring modified nucleotides and nucleosides or non-naturally occurring modified nucleotides and nucleosides. Such modifications can include those at the sugar, backbone, or nucleobase portion of the nucleotide and/or nucleoside as are recognized in the art.

In some embodiments, a naturally-occurring modified nucleotide or nucleotide of the disclosure is one as is generally known or recognized in the art. Non-limiting examples of such naturally occurring modified nucleotides and nucleotides can be found, inter alia, in the widely recognized MODOMICS database.

In some embodiments, a non-naturally occurring modified nucleotide or nucleoside of the disclosure is one as is generally known or recognized in the art. Non-limiting examples of such non-naturally occurring modified nucleotides and nucleosides can be found, inter alia, in published US application Nos. PCT/US2012/058519; PCT/US2013/075177; PCT/US2014/058897; PCT/US2014/058891; PCT/US2014/070413; PCT/US2015/036773; PCT/US2015/036759; PCT/US2015/036771; or PCT/IB 2017/051367 all of which are incorporated by reference herein.

Hence, nucleic acids of the disclosure ( e.g ., DNA nucleic acids and RNA nucleic acids, such as mRNA nucleic acids) can comprise standard nucleotides and nucleosides, naturally- occurring nucleotides and nucleosides, non-naturally-occurring nucleotides and nucleosides, or any combination thereof.

Nucleic acids of the disclosure (e.g., DNA nucleic acids and RNA nucleic acids, such as mRNA nucleic acids), in some embodiments, comprise various (more than one) different types of standard and/or modified nucleotides and nucleosides. In some embodiments, a particular region of a nucleic acid contains one, two or more (optionally different) types of standard and/or modified nucleotides and nucleosides.

In some embodiments, a modified RNA nucleic acid (e.g., a modified mRNA nucleic acid), introduced to a cell or organism, exhibits reduced degradation in the cell or organism, respectively, relative to an unmodified nucleic acid comprising standard nucleotides and nucleosides.

In some embodiments, a modified RNA nucleic acid (e.g., a modified mRNA nucleic acid), introduced into a cell or organism, may exhibit reduced immunogenicity in the cell or organism, respectively (e.g., a reduced innate response) relative to an unmodified nucleic acid comprising standard nucleotides and nucleosides.

Nucleic acids (e.g., RNA nucleic acids, such as mRNA nucleic acids), in some embodiments, comprise non-natural modified nucleotides that are introduced during synthesis or post-synthesis of the nucleic acids to achieve desired functions or properties. The modifications may be present on internucleotide linkages, purine or pyrimidine bases, or sugars. The modification may be introduced with chemical synthesis or with a polymerase enzyme at the terminal of a chain or anywhere else in the chain. Any of the regions of a nucleic acid may be chemically modified.

The present disclosure provides for modified nucleosides and nucleotides of a nucleic acid (e.g., RNA nucleic acids, such as mRNA nucleic acids). A “nucleoside” refers to a compound containing a sugar molecule (e.g., a pentose or ribose) or a derivative thereof in combination with an organic base (e.g., a purine or pyrimidine) or a derivative thereof (also referred to herein as “nucleobase”). A “nucleotide” refers to a nucleoside, including a phosphate group. Modified nucleotides may by synthesized by any useful method, such as, for example, chemically, enzymatically, or recombinantly, to include one or more modified or non-natural nucleosides. Nucleic acids can comprise a region or regions of linked nucleosides. Such regions may have variable backbone linkages. The linkages can be standard phosphodiester linkages, in which case the nucleic acids would comprise regions of nucleotides.

Modified nucleotide base pairing encompasses not only the standard adenosine-thymine, adenosine-uracil, or guanosine-cytosine base pairs, but also base pairs formed between nucleotides and/or modified nucleotides comprising non-standard or modified bases, wherein the arrangement of hydrogen bond donors and hydrogen bond acceptors permits hydrogen bonding between a non-standard base and a standard base or between two complementary non-standard base structures, such as, for example, in those nucleic acids having at least one chemical modification. One example of such non-standard base pairing is the base pairing between the modified nucleotide inosine and adenine, cytosine or uracil. Any combination of base/sugar or linker may be incorporated into nucleic acids of the present disclosure.

In some embodiments, modified nucleobases in nucleic acids (e.g., RNA nucleic acids, such as mRNA nucleic acids) comprise 1 -methyl-pseudouridine (hiΐy), 1 -ethyl-pseudouridine (eΐy), 5-methoxy-uridine (mo5U), 5-methyl-cytidine (m5C), and/or pseudouridine (y). In some embodiments, modified nucleobases in nucleic acids (e.g., RNA nucleic acids, such as mRNA nucleic acids) comprise 5-methoxymethyl uridine, 5-methylthio uridine, 1-methoxymethyl pseudouridine, 5-methyl cytidine, and/or 5-methoxy cytidine. In some embodiments, the polyribonucleotide includes a combination of at least two (e.g., 2, 3, 4 or more) of any of the aforementioned modified nucleobases, including but not limited to chemical modifications.

In some embodiments, a mRNA of the disclosure comprises 1 -methyl-pseudouridine (in 1 \ _[/) substitutions at one or more or all uridine positions of the nucleic acid.

In some embodiments, a mRNA of the disclosure comprises 1 -methyl-pseudouridine (m 1 \ _[/) substitutions at one or more or all uridine positions of the nucleic acid and 5-methyl cytidine substitutions at one or more or all cytidine positions of the nucleic acid.

In some embodiments, a mRNA of the disclosure comprises pseudouridine (y) substitutions at one or more or all uridine positions of the nucleic acid.

In some embodiments, a mRNA of the disclosure comprises pseudouridine (y) substitutions at one or more or all uridine positions of the nucleic acid and 5-methyl cytidine substitutions at one or more or all cytidine positions of the nucleic acid.

In some embodiments, a mRNA of the disclosure comprises uridine at one or more or all uridine positions of the nucleic acid.

In some embodiments, mRNAs are uniformly modified (e.g., fully modified, modified throughout the entire sequence) for a particular modification. For example, a nucleic acid can be uniformly modified with 1 -methyl-pseudouridine, meaning that all uridine residues in the mRNA sequence are replaced with 1 -methyl-pseudouridine. Similarly, a nucleic acid can be uniformly modified for any type of nucleoside residue present in the sequence by replacement with a modified residue such as those set forth above.

The nucleic acids of the present disclosure may be partially or fully modified along the entire length of the molecule. For example, one or more or all or a given type of nucleotide ( e.g ., purine or pyrimidine, or any one or more or all of A, G, U, C) may be uniformly modified in a nucleic acid of the disclosure, or in a predetermined sequence region thereof (e.g., in the mRNA including or excluding the poly (A) tail). In some embodiments, all nucleotides X in a nucleic acid of the present disclosure (or in a sequence region thereof) are modified nucleotides, wherein X may be any one of nucleotides A, G, U, C, or any one of the combinations A+G, A+U, A+C, G+U, G+C, U+C, A+G+U, A+G+C, G+U+C or A+G+C.

The nucleic acid may contain from about 1% to about 100% modified nucleotides (either in relation to overall nucleotide content, or in relation to one or more types of nucleotide, i.e., any one or more of A, G, U or C) or any intervening percentage (e.g., from 1% to 20%, from 1% to 25%, from 1% to 50%, from 1% to 60%, from 1% to 70%, from 1% to 80%, from 1% to 90%, from 1% to 95%, from 10% to 20%, from 10% to 25%, from 10% to 50%, from 10% to 60%, from 10% to 70%, from 10% to 80%, from 10% to 90%, from 10% to 95%, from 10% to 100%, from 20% to 25%, from 20% to 50%, from 20% to 60%, from 20% to 70%, from 20% to 80%, from 20% to 90%, from 20% to 95%, from 20% to 100%, from 50% to 60%, from 50% to 70%, from 50% to 80%, from 50% to 90%, from 50% to 95%, from 50% to 100%, from 70% to 80%, from 70% to 90%, from 70% to 95%, from 70% to 100%, from 80% to 90%, from 80% to 95%, from 80% to 100%, from 90% to 95%, from 90% to 100%, and from 95% to 100%). It will be understood that any remaining percentage is accounted for by the presence of unmodified A, G, U, or C.

The mRNAs may contain at a minimum 1% and at maximum 100% modified nucleotides, or any intervening percentage, such as at least 5% modified nucleotides, at least 10% modified nucleotides, at least 25% modified nucleotides, at least 50% modified nucleotides, at least 80% modified nucleotides, or at least 90% modified nucleotides. For example, the nucleic acids may contain a modified pyrimidine such as a modified uracil or cytosine. In some embodiments, at least 5%, at least 10%, at least 25%, at least 50%, at least 80%, at least 90% or 100% of the uracil in the nucleic acid is replaced with a modified uracil (e.g., a 5-substituted uracil). The modified uracil can be replaced by a compound having a single unique structure or can be replaced by a plurality of compounds having different structures (e.g., 2, 3, 4 or more unique structures). In some embodiments, at least 5%, at least 10%, at least 25%, at least 50%, at least 80%, at least 90% or 100% of the cytosine in the nucleic acid is replaced with a modified cytosine (e.g., a 5-substituted cytosine). The modified cytosine can be replaced by a compound having a single unique structure or can be replaced by a plurality of compounds having different structures ( e.g ., 2, 3, 4 or more unique structures).

Untranslated Regions (UTRs)

The ruRNAs of the present disclosure may comprise one or more regions or parts which act or function as an untranslated region. Where mRNAs are designed to encode at least one antigen of interest, the nucleic may comprise one or more of these untranslated regions (UTRs). Wild-type untranslated regions of a nucleic acid are transcribed but not translated. In mRNA, the 5' UTR starts at the transcription start site and continues to the start codon but does not include the start codon; whereas, the 3' UTR starts immediately following the stop codon and continues until the transcriptional termination signal. There is growing body of evidence about the regulatory roles played by the UTRs in terms of stability of the nucleic acid molecule and translation. The regulatory features of a UTR can be incorporated into the RNAs of the present disclosure to, among other things, enhance the stability of the molecule. The specific features can also be incorporated to ensure controlled down-regulation of the transcript in case they are misdirected to undesired organs sites. A variety of 5 ’UTR and 3 ’UTR sequences are known and available in the art.

A 5 ¹ UTR is region of an mRNA that is directly upstream (5 ¹ ) from the start codon (the first codon of an mRNA transcript translated by a ribosome). A 5 ¹ UTR does not encode a protein (is non-coding). Natural 5 'UTRs have features that play roles in translation initiation. They harbor signatures like Kozak sequences which are commonly known to be involved in the process by which the ribosome initiates translation of many genes. Kozak sequences have the consensus CCR(A/G)CCAUGG, where R is a purine (adenine or guanine) three bases upstream of the start codon (AUG), which is followed by another 'G'.5'UTR also have been known to form secondary structures which are involved in elongation factor binding.

In some embodiments of the disclosure, a 5’ UTR is a heterologous UTR, i.e., is a UTR found in nature associated with a different ORF. In another embodiment, a 5’ UTR is a synthetic UTR, i.e., does not occur in nature. Synthetic UTRs include UTRs that have been mutated to improve their properties, e.g., which increase gene expression as well as those which are completely synthetic. Exemplary 5’ UTRs include Xenopus or human derived a-globin or b- globin (8278063; 9012219), human cytochrome b-245 a polypeptide, and hydroxysteroid (17b) dehydrogenase, and Tobacco etch virus (US 8,278,063; US 9,012,219). CMV immediate-early 1 (IE1) gene (US 2014/0206753; WO 2013/185069), the sequence GGGAUCCUACC (SEQ ID NO: 33) (WO 2014/144196) may also be used. In another embodiment, 5' UTR of a TOP gene is a 5' UTR of a TOP gene lacking the 5' TOP motif (the oligopyrimidine tract) (e.g., WO 2015/101414; WO 2015/101415; WO 2015/062738; WO 2015/024667; WO 2015/024667; 5' UTR element derived from ribosomal protein Large 32 (L32) gene (WO 2015/101414; WO 2015/101415; WO 2015/062738), 5' UTR element derived from the 5' UTR of an hydroxysteroid (17-b) dehydrogenase 4 gene (HSD17B4) (WO 2015/024667), or a 5' UTR element derived from the 5' UTR of ATP5A1 (WO 2015/024667) can be used. In some embodiments, an internal ribosome entry site (IRES) is used instead of a 5' UTR.

In some embodiments, a 5' UTR of the present disclosure comprises a sequence selected from SEQ ID NO: 2 and SEQ ID NO: 12.

A 3' UTR is region of an mRNA that is directly downstream (3 ¹ ) from the stop codon (the codon of an mRNA transcript that signals a termination of translation). A 3' UTR does not encode a protein (is non-coding). Natural or wild type 3' UTRs are known to have stretches of adenosines and uridines embedded in them. These AU rich signatures are particularly prevalent in genes with high rates of turnover. Based on their sequence features and functional properties, the AU rich elements (AREs) can be separated into three classes (Chen et al, 1995): Class I AREs contain several dispersed copies of an AUUUA motif within U-rich regions. C-Myc and MyoD contain class I AREs. Class II AREs possess two or more overlapping UUAUUUA(U/A)(U/A) (SEQ ID NO: 34) nonamers. Molecules containing this type of AREs include GM-CSF and TNF-a. Class III ARES are less well defined. These U rich regions do not contain an AUUUA motif. c-Jun and Myogenin are two well-studied examples of this class.

Most proteins binding to the AREs are known to destabilize the messenger, whereas members of the ELAV family, most notably HuR, have been documented to increase the stability of mRNA. HuR binds to AREs of all the three classes. Engineering the HuR specific binding sites into the 3' UTR of nucleic acid molecules will lead to HuR binding and thus, stabilization of the message in vivo.

Introduction, removal or modification of 3' UTR AU rich elements (AREs) can be used to modulate the stability of nucleic acids ( e.g ., RNA) of the disclosure. When engineering specific nucleic acids, one or more copies of an ARE can be introduced to make nucleic acids of the disclosure less stable and thereby curtail translation and decrease production of the resultant protein. Likewise, AREs can be identified and removed or mutated to increase the intracellular stability and thus increase translation and production of the resultant protein. Transfection experiments can be conducted in relevant cell lines, using nucleic acids of the disclosure and protein production can be assayed at various time points post-transfection. For example, cells can be transfected with different ARE-engineering molecules and by using an ELISA kit to the relevant protein and assaying protein produced at 6 hour, 12 hour, 24 hour, 48 hour, and 7 days post-transfection. 3' UTRs may be heterologous or synthetic. With respect to 3’ UTRs, globin UTRs, including Xenopus b-globin UTRs and human b-globin UTRs are known in the art (US 8,278,063; US 9,012,219; US 2011/0086907). A modified b-globin molecule with enhanced stability in some cell types by cloning two sequential human b-globin 3 ’UTRs head to tail has been developed and is well known in the art (US 2012/0195936; WO 2014/071963). In addition, a2-globin, a 1 -globin, UTRs and mutants thereof are also known in the art (WO 2015/101415; WO 2015/024667). Other 3 UTRs described in the mRNAs in the non-patent literature include CYBA (Ferizi et ah, 2015) and albumin (Thess et ah, 2015). Other exemplary 3 UTRs include that of bovine or human growth hormone (wild type or modified) (W 02013/185069; US 2014/0206753; WO 2014/152774), rabbit b globin and hepatitis B virus (HBV), a-globin 3' UTR and Viral VEEV 3’ UTR sequences are also known in the art. In some embodiments, the sequence UUUGAAUU (WO 2014/144196) is used. In some embodiments, 3 UTRs of human and mouse ribosomal protein are used. Other examples include rps93’UTR (WO 2015/101414), FIG4 (WO 2015/101415), and human albumin 7 (WO 2015/101415).

In some embodiments, a 3 ¹ UTR of the present disclosure comprises a sequence selected from SEQ ID NO: 4 and SEQ ID NO: 13.

Those of ordinary skill in the art will understand that 5 ’UTRs that are heterologous or synthetic may be used with any desired 3’ UTR sequence. For example, a heterologous 5’UTR may be used with a synthetic 3’UTR with a heterologous 3’ UTR.

Non-UTR sequences may also be used as regions or subregions within a nucleic acid. For example, introns or portions of introns sequences may be incorporated into regions of nucleic acid of the disclosure. Incorporation of intronic sequences may increase protein production as well as nucleic acid levels.

Combinations of features may be included in flanking regions and may be contained within other features. For example, the ORF may be flanked by a 5' UTR which may contain a strong Kozak translational initiation signal and/or a 3' UTR which may include an oligo(dT) sequence for templated addition of a poly-A tail. 5' UTR may comprise a first polynucleotide fragment and a second polynucleotide fragment from the same and/or different genes such as the 5' UTRs described in US Patent Application Publication No. 20100293625 and PCT/US2014/069155, herein incorporated by reference in its entirety.

It should be understood that any UTR from any gene may be incorporated into the regions of a nucleic acid. Furthermore, multiple wild-type UTRs of any known gene may be utilized. It is also within the scope of the present disclosure to provide artificial UTRs which are not variants of wild type regions. These UTRs or portions thereof may be placed in the same orientation as in the transcript from which they were selected or may be altered in orientation or location. Hence a 5' or 3' UTR may be inverted, shortened, lengthened, made with one or more other 5' UTRs or 3' UTRs. As used herein, the term “altered” as it relates to a UTR sequence, means that the UTR has been changed in some way in relation to a reference sequence. For example, a 3' UTR or 5' UTR may be altered relative to a wild-type or native UTR by the change in orientation or location as taught above or may be altered by the inclusion of additional nucleotides, deletion of nucleotides, swapping or transposition of nucleotides. Any of these changes producing an “altered” UTR (whether 3' or 5') comprise a variant UTR.

In some embodiments, a double, triple or quadruple UTR such as a 5' UTR or 3' UTR may be used. As used herein, a “double” UTR is one in which two copies of the same UTR are encoded either in series or substantially in series. For example, a double beta-globin 3' UTR may be used as described in US Patent publication 20100129877, the contents of which are incorporated herein by reference in its entirety.

It is also within the scope of the present disclosure to have patterned UTRs. As used herein “patterned UTRs” are those UTRs which reflect a repeating or alternating pattern, such as ABABAB or AABBAABBAABB or ABCABCABC or variants thereof repeated once, twice, or more than 3 times. In these patterns, each letter, A, B, or C represent a different UTR at the nucleotide level.

In some embodiments, flanking regions are selected from a family of transcripts whose proteins share a common function, structure, feature or property. For example, polypeptides of interest may belong to a family of proteins which are expressed in a particular cell, tissue or at some time during development. The UTRs from any of these genes may be swapped for any other UTR of the same or different family of proteins to create a new polynucleotide. As used herein, a “family of proteins” is used in the broadest sense to refer to a group of two or more polypeptides of interest which share at least one function, structure, feature, localization, origin, or expression pattern.

The untranslated region may also include translation enhancer elements (TEE). As a non limiting example, the TEE may include those described in US Application No.20090226470, herein incorporated by reference in its entirety, and those known in the art.

In vitro Transcription of RNA cDNA encoding the RNAs described herein may be transcribed using an in vitro transcription (IVT) system. In vitro transcription of RNA is known in the art and is described in International Publication WO 2014/152027, which is incorporated by reference herein in its entirety. In some embodiments, the RNA of the present disclosure is prepared in accordance with any one or more of the methods described in WO 2018/053209 and WO 2019/036682, each of which is incorporated by reference herein. In some embodiments, the RNA transcript is generated using a non-amplified, linearized DNA template in an in vitro transcription reaction to generate the RNA transcript. In some embodiments, the template DNA is isolated DNA. In some embodiments, the template DNA is cDNA. In some embodiments, the cDNA is formed by reverse transcription of an RNA, for example, but not limited to coronavirus mRNA. In some embodiments, cells, e.g., bacterial cells, e.g., E. coli, e.g., DH-1 cells are transfected with the plasmid DNA template. In some embodiments, the transfected cells are cultured to replicate the plasmid DNA which is then isolated and purified. In some embodiments, the DNA template includes a RNA polymerase promoter, e.g., a T7 promoter located 5 ' to and operably linked to the gene of interest.

In some embodiments, an in vitro transcription template encodes a 5' untranslated (UTR) region, contains an open reading frame, and encodes a 3' UTR and a poly(A) tail. The particular nucleic acid sequence composition and length of an in vitro transcription template will depend on the mRNA encoded by the template.

A “5' untranslated region” (UTR) refers to a region of an mRNA that is directly upstream (i.e., 5') from the start codon (i.e., the first codon of an mRNA transcript translated by a ribosome) that does not encode a polypeptide. When RNA transcripts are being generated, the 5’ UTR may comprise a promoter sequence. Such promoter sequences are known in the art. It should be understood that such promoter sequences will not be present in a vaccine of the disclosure.

A “3' untranslated region” (UTR) refers to a region of an mRNA that is directly downstream (i.e., 3') from the stop codon (i.e., the codon of an mRNA transcript that signals a termination of translation) that does not encode a polypeptide.

An “open reading frame” is a continuous stretch of DNA beginning with a start codon (e.g., methionine (ATG)), and ending with a stop codon (e.g., TAA, TAG or TGA) and encodes a polypeptide.

A “poly(A) tail” is a region of mRNA that is downstream, e.g., directly downstream (i.e., 3'), from the 3' UTR that contains multiple, consecutive adenosine monophosphates. A poly(A) tail may contain 10 to 300 adenosine monophosphates. For example, a poly(A) tail may contain 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210,

220, 230, 240, 250, 260, 270, 280, 290 or 300 adenosine monophosphates. In some embodiments, a poly(A) tail contains 50 to 250 adenosine monophosphates. In a relevant biological setting (e.g., in cells, in vivo ) the poly(A) tail functions to protect mRNA from enzymatic degradation, e.g., in the cytoplasm, and aids in transcription termination, and/or export of the mRNA from the nucleus and translation. In some embodiments, a nucleic acid includes 200 to 3,000 nucleotides. For example, a nucleic acid may include 200 to 500, 200 to 1000, 200 to 1500, 200 to 3000, 500 to 1000, 500 to 1500, 500 to 2000, 500 to 3000, 1000 to 1500, 1000 to 2000, 1000 to 3000, 1500 to 3000, or 2000 to 3000 nucleotides).

An in vitro transcription system typically comprises a transcription buffer, nucleotide triphosphates (NTPs), an RNase inhibitor and a polymerase.

The NTPs may be manufactured in house, may be selected from a supplier, or may be synthesized as described herein. The NTPs may be selected from, but are not limited to, those described herein including natural and unnatural (modified) NTPs.

Any number of RNA polymerases or variants may be used in the method of the present disclosure. The polymerase may be selected from, but is not limited to, a phage RNA polymerase, e.g., a T7 RNA polymerase, a T3 RNA polymerase, a SP6 RNA polymerase, and/or mutant polymerases such as, but not limited to, polymerases able to incorporate modified nucleic acids and/or modified nucleotides, including chemically modified nucleic acids and/or nucleotides. Some embodiments exclude the use of DNase.

In some embodiments, the RNA transcript is capped via enzymatic capping. In some embodiments, the RNA comprises 5' terminal cap, for example, 7mG(5’)ppp(5’)NlmpNp.

Chemical Synthesis

Solid-phase chemical synthesis. Nucleic acids the present disclosure may be manufactured in whole or in part using solid phase techniques. Solid-phase chemical synthesis of nucleic acids is an automated method wherein molecules are immobilized on a solid support and synthesized step by step in a reactant solution. Solid-phase synthesis is useful in site-specific introduction of chemical modifications in the nucleic acid sequences.

Liquid Phase Chemical Synthesis. The synthesis of nucleic acids of the present disclosure by the sequential addition of monomer building blocks may be carried out in a liquid phase.

Combination of Synthetic Methods. The synthetic methods discussed above each has its own advantages and limitations. Attempts have been conducted to combine these methods to overcome the limitations. Such combinations of methods are within the scope of the present disclosure. The use of solid-phase or liquid-phase chemical synthesis in combination with enzymatic ligation provides an efficient way to generate long chain nucleic acids that cannot be obtained by chemical synthesis alone.

Ligation of Nucleic Acid Regions or Subregions

Assembling nucleic acids by a ligase may also be used. DNA or RNA ligases promote intermolecular ligation of the 5’ and 3’ ends of polynucleotide chains through the formation of a phosphodiester bond. Nucleic acids such as chimeric polynucleotides and/or circular nucleic acids may be prepared by ligation of one or more regions or subregions. DNA fragments can be joined by a ligase catalyzed reaction to create recombinant DNA with different functions. Two oligodeoxynucleotides, one with a 5’ phosphoryl group and another with a free 3’ hydroxyl group, serve as substrates for a DNA ligase.

Purification

Purification of the nucleic acids described herein may include, but is not limited to, nucleic acid clean-up, quality assurance and quality control. Clean-up may be performed by methods known in the arts such as, but not limited to, AGENCOURT® beads (Beckman Coulter Genomics, Danvers, MA), poly-T beads, LNATM oligo-T capture probes (EXIQON® Inc, Vedbaek, Denmark) or HPLC based purification methods such as, but not limited to, strong anion exchange HPLC, weak anion exchange HPLC, reverse phase HPLC (RP-HPLC), and hydrophobic interaction HPLC (HIC-HPLC). The term “purified” when used in relation to a nucleic acid such as a “purified nucleic acid” refers to one that is separated from at least one contaminant. A “contaminant” is any substance that makes another unfit, impure or inferior. Thus, a purified nucleic acid (e.g., DNA and RNA) is present in a form or setting different from that in which it is found in nature, or a form or setting different from that which existed prior to subjecting it to a treatment or purification method.

A quality assurance and/or quality control check may be conducted using methods such as, but not limited to, gel electrophoresis, UV absorbance, or analytical HPLC.

In some embodiments, the nucleic acids may be sequenced by methods including, but not limited to reverse-transcriptase-PCR.

Quantification

In some embodiments, the nucleic acids of the present disclosure may be quantified in exosomes or when derived from one or more bodily fluid. Bodily fluids include peripheral blood, serum, plasma, ascites, urine, cerebrospinal fluid (CSL), sputum, saliva, bone marrow, synovial fluid, aqueous humor, amniotic fluid, cerumen, breast milk, broncheo alveolar lavage fluid, semen, prostatic fluid, cowper's fluid or pre-ejaculatory fluid, sweat, fecal matter, hair, tears, cyst fluid, pleural and peritoneal fluid, pericardial fluid, lymph, chyme, chyle, bile, interstitial fluid, menses, pus, sebum, vomit, vaginal secretions, mucosal secretion, stool water, pancreatic juice, lavage fluids from sinus cavities, bronchopulmonary aspirates, blastocyl cavity fluid, and umbilical cord blood. Alternatively, exosomes may be retrieved from an organ selected from the group consisting of lung, heart, pancreas, stomach, intestine, bladder, kidney, ovary, testis, skin, colon, breast, prostate, brain, esophagus, liver, and placenta. Assays may be performed using specific probes, cytometry, qRT-PCR, real-time PCR, PCR, flow cytometry, electrophoresis, mass spectrometry, or combinations thereof while the exosomes may be isolated using immunohistochemical methods such as enzyme linked immunosorbent assay (ELISA) methods. Exosomes may also be isolated by size exclusion chromatography, density gradient centrifugation, differential centrifugation, nanomembrane ultrafiltration, immunoabsorbent capture, affinity purification, microfluidic separation, or combinations thereof.

These methods afford the investigator the ability to monitor, in real time, the level of nucleic acids remaining or delivered. This is possible because the nucleic acids of the present disclosure, in some embodiments, differ from the endogenous forms due to the structural or chemical modifications.

In some embodiments, the nucleic acid may be quantified using methods such as, but not limited to, ultraviolet visible spectroscopy (UV/Vis). A non-limiting example of a UV/Vis spectrometer is a NANODROP® spectrometer (ThermoFisher, Waltham, MA). The quantified nucleic acid may be analyzed in order to determine if the nucleic acid may be of proper size, check that no degradation of the nucleic acid has occurred. Degradation of the nucleic acid may be checked by methods such as, but not limited to, agarose gel electrophoresis, HPLC based purification methods such as, but not limited to, strong anion exchange HPLC, weak anion exchange HPLC, reverse phase HPLC (RP-HPLC), and hydrophobic interaction HPLC (HIC- HPLC), liquid chromatography-mass spectrometry (LCMS), capillary electrophoresis (CE) and capillary gel electrophoresis (CGE).

Lipid Nanoparticles (LNPs)

In some embodiments, the RNA ( e.g ., mRNA) of the disclosure is formulated in a lipid nanoparticle (LNP). Lipid nanoparticles typically comprise ionizable amino lipid, non-cationic lipid, sterol and PEG lipid components along with the nucleic acid cargo of interest. The lipid nanoparticles of the disclosure can be generated using components, compositions, and methods as are generally known in the art, see for example PCT/US2016/052352; PCT/US2016/068300; PCT/US2017/037551; PCT/US2015/027400; PCT/US2016/047406; PCT/US2016/000129; PCT/US2016/014280; PCT/US2016/014280; PCT/US2017/038426; PCT/US2014/027077; PCT/US2014/055394; PCT/US2016/052117; PCT/US2012/069610; PCT/US2017/027492; PCT/US2016/059575 and PCT/US2016/069491 all of which are incorporated by reference herein in their entirety.

Vaccines of the present disclosure are typically formulated in lipid nanoparticle. In some embodiments, the lipid nanoparticle comprises at least one ionizable amino lipid, at least one non-cationic lipid, at least one sterol, and/or at least one polyethylene glycol (PEG)-modified lipid.

In some embodiments, the lipid nanoparticle comprises 20-60 mol% ionizable amino lipid. For example, the lipid nanoparticle may comprise 20-50 mol%, 20-40 mol%, 20-30 mol%, 30-60 mol%, 30-50 mol%, 30-40 mol%, 40-60 mol%, 40-50 mol%, or 50-60 mol% ionizable amino lipid. In some embodiments, the lipid nanoparticle comprises 20 mol%, 30 mol%, 40 mol%, 50 mol%, or 60 mol% ionizable amino lipid.

In some embodiments, the lipid nanoparticle comprises 5-25 mol% non-cationic lipid.

For example, the lipid nanoparticle may comprise 5-20 mol%, 5-15 mol%, 5-10 mol%, 10-25 mol%, 10-20 mol%, 10-25 mol%, 15-25 mol%, 15-20 mol%, or 20-25 mol% non-cationic lipid. In some embodiments, the lipid nanoparticle comprises 5 mol%, 10 mol%, 15 mol%, 20 mol%, or 25 mol% non-cationic lipid.

In some embodiments, the lipid nanoparticle comprises 25-55 mol% sterol. For example, the lipid nanoparticle may comprise 25-50 mol%, 25-45 mol%, 25-40 mol%, 25-35 mol%, 25-30 mol%, 30-55 mol%, 30-50 mol%, 30-45 mol%, 30-40 mol%, 30-35 mol%, 35-55 mol%, 35-50 mol%, 35-45 mol%, 35-40 mol%, 40-55 mol%, 40-50 mol%, 40-45 mol%, 45-55 mol%, 45-50 mol%, or 50-55 mol% sterol. In some embodiments, the lipid nanoparticle comprises 25 mol%, 30 mol%, 35 mol%, 40 mol%, 45 mol%, 50 mol%, or 55 mol% sterol.

In some embodiments, the lipid nanoparticle comprises 0.5-15 mol% PEG-modified lipid. For example, the lipid nanoparticle may comprise 0.5-10 mol%, 0.5-5 mol%, 1-15 mol%, 1-10 mol%, 1-5 mol%, 2-15 mol%, 2-10 mol%, 2-5 mol%, 5-15 mol%, 5-10 mol%, or 10-15 mol%.

In some embodiments, the lipid nanoparticle comprises 0.5 mol%, 1 mol%, 2 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol%, 11 mol%, 12 mol%, 13 mol%, 14 mol%, or 15 mol% PEG-modified lipid.

In some embodiments, the lipid nanoparticle comprises 20-60 mol% ionizable amino lipid, 5-25 mol% non-cationic lipid, 25-55 mol% sterol, and 0.5-15 mol% PEG-modified lipid.

In some embodiments, an ionizable amino lipid of the disclosure comprises a compound of Formula (I): or a salt or isomer thereof, wherein:

Ri is selected from the group consisting of C5-30 alkyl, C5-20 alkenyl, -R*YR”, -YR”, and -R”M’R’;

R ₂ and R ₃ are independently selected from the group consisting of H, Ci- ₁₄ alkyl, C _2-14 alkenyl, -R*YR”, -YR”, and -R*OR”, or R ₂ and R ₃ , together with the atom to which they are attached, form a heterocycle or carbocycle;

R ₄ is selected from the group consisting of a C _3-6 carbocycle, -(CH ₂ ) _n Q, -(CH ₂ ) _n CHQR, -CHQR, -CQ(R) ₂ , and unsubstituted Ci- ₆ alkyl, where Q is selected from a carbocycle, heterocycle, -OR, -0(CH ₂ )nN(R) ₂ , -C(0)OR, -OC(0)R, -CX ₃ , -CX ₂ H, -CXH ₂ , -CN, -N(R) ₂ , -C(0)N(R)2, -N(R)C(0)R, -N(R)S(0) ₂ R, -N(R)C(0)N(R)2, -N(R)C(S)N(R)2, -N(R)RS, -0(CH ₂ )nOR, -N(R)C(=NR ₉ )N(R)2, -N(R)C(=CHR ₉ )N(R) ₂ , -OC(0)N(R) ₂ , -N(R)C(0)OR, -N(OR)C(0)R, -N(OR)S(0) ₂ R, -N(OR)C(0)OR, -N(OR)C(0)N(R) ₂ , -N(OR)C(S)N(R) ₂ , -N(0R)C(=NR ₉ )N(R) ₂ , -N(0R)C(=CHR ₉ )N(R) ₂ , -C(=NR ₉ )N(R)2, -C(=NR ₉ )R, -C(0)N(R)OR, and -C(R)N(R) ₂ C(0)OR, and each n is independently selected from 1, 2, 3, 4, and 5; each R5 is independently selected from the group consisting of C1-3 alkyl, C _2-3 alkenyl, and H; each R ₆ is independently selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H;

M and M’ are independently selected from -C(0)0-, -OC(O)-, -C(0)N(R’)-,

-N(R’)C(0)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(0)(0R’)0-, -S(0) ₂ -, -S-S-, an aryl group, and a heteroaryl group;

R ₇ is selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H;

Rs is selected from the group consisting of C _3-6 carbocycle and heterocycle;

R ₉ is selected from the group consisting of H, CN, NO ₂ , Ci- ₆ alkyl, -OR, -S(0) ₂ R, -S(0) ₂ N(R)2, C2-6 alkenyl, C3-6 carbocycle and heterocycle; each R is independently selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H; each R’ is independently selected from the group consisting of C _1-18 alkyl, C _2-18 alkenyl, -R*YR”, -YR”, and H; each R” is independently selected from the group consisting of C _3-14 alkyl and C _3-14 alkenyl; each R* is independently selected from the group consisting of Ci- ₁₂ alkyl and C _2-12 alkenyl; each Y is independently a C3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13. In some embodiments, a subset of compounds of Formula (I) includes those in which when R ₄ is -(CH ₂ ) _n Q, -(CH ₂ ) _n CHQR, -CHQR, or -CQ(R) ₂ , then (i) Q is not -N(R) ₂ when n is 1, 2, 3, 4 or 5, or (ii) Q is not 5, 6, or 7-membered heterocycloalkyl when n is 1 or 2.

In some embodiments, another subset of compounds of Formula (I) includes those in which

Ri is selected from the group consisting of C5-30 alkyl, Cs- ₂ o alkenyl, -R*YR”, -YR”, and -R”M’R’;

R ₂ and R3 are independently selected from the group consisting of H, Ci- ₁₄ alkyl, C _2-i 4 alkenyl, -R*YR”, -YR”, and -R*OR”, or R ₂ and R3, together with the atom to which they are attached, form a heterocycle or carbocycle;

R4 is selected from the group consisting of a C3-6 carbocycle, -(CH ₂ ) _n Q, -(CH ₂ ) _n CHQR, -CHQR, -CQ(R) ₂ , and unsubstituted Ci- ₆ alkyl, where Q is selected from a C3-6 carbocycle, a 5- to 14-membered heteroaryl having one or more heteroatoms selected from N, O, and S, -OR, -0(CH ₂ )„N(R) ₂ , -C(0)OR, -OC(0)R, -CX ₃ , -CX ₂ H, -CXH ₂ , -CN, -C(0)N(R) ₂ , -N(R)C(0)R, -N(R)S(0) ₂ R, -N(R)C(0)N(R) ₂ , -N(R)C(S)N(R) ₂ , -CRN(R) ₂ C(0)OR, -N(R)R _S , -0(CH ₂ )„OR, -N(R)C(=NR ₉ )N(R) ₂ , -N(R)C(=CHR ₉ )N(R) ₂ , -OC(0)N(R) ₂ , -N(R)C(0)OR, -N(OR)C(0)R, -N(OR)S(0) ₂ R, -N(OR)C(0)OR, -N(OR)C(0)N(R) ₂ , -N(OR)C(S)N(R) ₂ , -N(OR)C(=NR ₉ )N(R) ₂ , -N(OR)C(=CHR ₉ )N(R) ₂ , -C(=NR ₉ )N(R) ₂ , -C(=NR ₉ )R, -C(0)N(R)OR, and a 5- to 14-membered heterocycloalkyl having one or more heteroatoms selected from N, O, and S which is substituted with one or more substituents selected from oxo (=0), OH, amino, mono- or di-alkylamino, and Ci-3 alkyl, and each n is independently selected from 1, 2, 3, 4, and 5; each R5 is independently selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H; each R ₆ is independently selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H;

M and M’ are independently selected from -C(0)0-, -OC(O)-, -C(0)N(R’)-,

-N(R’)C(0)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(0)(OR’)0-, -S(0) ₂ -, -S-S-, an aryl group, and a heteroaryl group;

R ₇ is selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H;

Rs is selected from the group consisting of C _3-6 carbocycle and heterocycle;

R ₉ is selected from the group consisting of H, CN, N0 ₂ , Ci- ₆ alkyl, -OR, -S(0) ₂ R, -S(0) ₂ N(R) ₂ , C _2-6 alkenyl, C3-6 carbocycle and heterocycle; each R is independently selected from the group consisting of C1-3 alkyl, C ₂ -3 alkenyl, and H; each R’ is independently selected from the group consisting of Ci-is alkyl, C _2-i s alkenyl, -R*YR”, -YR”, and H; each R” is independently selected from the group consisting of C3-14 alkyl and C3-14 alkenyl; each R* is independently selected from the group consisting of Ci-12 alkyl and C2-12 alkenyl; each Y is independently a C3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

In some embodiments, another subset of compounds of Formula (I) includes those in which

Ri is selected from the group consisting of C5-30 alkyl, C5-20 alkenyl, -R*YR”, -YR”, and -R”M’R’;

R2 and R3 are independently selected from the group consisting of H, Ci-14 alkyl, C2-14 alkenyl, -R*YR”, -YR”, and -R*OR”, or R2 and R3, together with the atom to which they are attached, form a heterocycle or carbocycle;

R4 is selected from the group consisting of a C3-6 carbocycle, -(CH2) _n Q, -(CH2) _n CHQR, -CHQR, -CQ(R)2, and unsubstituted Ci- ₆ alkyl, where Q is selected from a C3-6 carbocycle, a 5- to 14-membered heterocycle having one or more heteroatoms selected from N, O, and S, -OR, -0(CH ₂ )nN(R) ₂ , -C(0)OR, -OC(0)R, -CX ₃ , -CX ₂ H, -CXH ₂ , -CN, -C(0)N(R) ₂ , -N(R)C(0)R, -N(R)S(0) ₂ R, -N(R)C(0)N(R)2, -N(R)C(S)N(R)2, -CRN(R) ₂ C(0)OR, -N(R)RS, -0(CH ₂ ) _n OR, -N(R)C(=NR ₉ )N(R)2, -N(R)C(=CHR ₉ )N(R) ₂ , -0C(0)N(R)2, -N(R)C(0)OR, -N(OR)C(0)R, -N(OR)S(0) ₂ R, -N(OR)C(0)OR, -N(0R)C(0)N(R)2, -N(0R)C(S)N(R)2, -N(0R)C(=NR ₉ )N(R) ₂ , -N(0R)C(=CHR ₉ )N(R) ₂ , -C(=NR ₉ )R, -C(0)N(R)OR, and -C(=NR ₉ )N(R) ₂ , and each n is independently selected from 1, 2, 3, 4, and 5; and when Q is a 5- to 14-membered heterocycle and (i) R4 is -(CH2) _n Q in which n is 1 or 2, or (ii) R4 is -(CH2) _n CHQR in which n is 1, or (iii) R4 is -CHQR, and -CQ(R)2, then Q is either a 5- to 14-membered heteroaryl or 8- to 14-membered heterocycloalkyl; each R5 is independently selected from the group consisting of C1-3 alkyl, C2-3 alkenyl, and H; each R ₆ is independently selected from the group consisting of C1-3 alkyl, C2-3 alkenyl, and H;

M and M’ are independently selected from -C(0)0-, -OC(O)-, -C(0)N(R’)-,

-N(R’)C(0)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(0)(0R’)0-, -S(0) ₂ -, -S-S-, an aryl group, and a heteroaryl group; R ₇ is selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H;

Rs is selected from the group consisting of C _3-6 carbocycle and heterocycle;

R ₉ is selected from the group consisting of H, CN, NO ₂ , Ci- ₆ alkyl, -OR, -S(0) ₂ R, -S(0) ₂ N(R)2, C2-6 alkenyl, C3-6 carbocycle and heterocycle; each R is independently selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H; each R’ is independently selected from the group consisting of C _1-18 alkyl, C _2-18 alkenyl, -R*YR”, -YR”, and H; each R” is independently selected from the group consisting of C _3-14 alkyl and C _3-14 alkenyl; each R* is independently selected from the group consisting of Ci- ₁₂ alkyl and C _2-12 alkenyl; each Y is independently a C _3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

In some embodiments, another subset of compounds of Formula (I) includes those in which

Ri is selected from the group consisting of C _5-30 alkyl, C _5-20 alkenyl, -R*YR”, -YR”, and -R”M’R’;

R ₂ and R ₃ are independently selected from the group consisting of H, Ci- ₁₄ alkyl, C _2-14 alkenyl, -R*YR”, -YR”, and -R*OR”, or R ₂ and R ₃ , together with the atom to which they are attached, form a heterocycle or carbocycle;

R ₄ is selected from the group consisting of a C _3-6 carbocycle, -(CH ₂ ) _n Q, -(CH ₂ ) _n CHQR, -CHQR, -CQ(R) ₂ , and unsubstituted Ci- ₆ alkyl, where Q is selected from a C _3-6 carbocycle, a 5- to 14-membered heteroaryl having one or more heteroatoms selected from N, O, and S, -OR, -0(CH ₂ )nN(R) ₂ , -C(0)OR, -OC(0)R, -CX ₃ , -CX ₂ H, -CXH ₂ , -CN, -C(0)N(R) ₂ , -N(R)C(0)R, -N(R)S(0) ₂ R, -N(R)C(0)N(R)2, -N(R)C(S)N(R)2, -CRN(R) ₂ C(0)OR, -N(R)RS, -0(CH ₂ ) _n OR, -N(R)C(=NR ₉ )N(R)2, -N(R)C(=CHR ₉ )N(R) ₂ , -0C(0)N(R)2, -N(R)C(0)OR, -N(OR)C(0)R, -N(OR)S(0) ₂ R, -N(OR)C(0)OR, -N(0R)C(0)N(R)2, -N(0R)C(S)N(R)2, -N(0R)C(=NR ₉ )N(R) ₂ , -N(0R)C(=CHR ₉ )N(R) ₂ , -C(=NR ₉ )R, -C(0)N(R)OR, and -C(=NR ₉ )N(R) ₂ , and each n is independently selected from 1, 2, 3, 4, and 5; each R ₅ is independently selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H; each R ₆ is independently selected from the group consisting of C1-3 alkyl, C2-3 alkenyl, and H;

M and M’ are independently selected from -C(0)0-, -OC(O)-, -C(0)N(R’)-,

-N(R’)C(0)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(0)(0R’)0-, -S(0) ₂ -, -S-S-, an aryl group, and a heteroaryl group;

R ₇ is selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H;

Rs is selected from the group consisting of C _3-6 carbocycle and heterocycle;

R9 is selected from the group consisting of H, CN, NO2, Ci-6 alkyl, -OR, -S(0)2R, -S(0) ₂ N(R)2, C2-6 alkenyl, C3-6 carbocycle and heterocycle; each R is independently selected from the group consisting of C1-3 alkyl, C2-3 alkenyl, and H; each R’ is independently selected from the group consisting of Ci-is alkyl, C2-18 alkenyl, -R*YR”, -YR”, and H; each R” is independently selected from the group consisting of C _3-14 alkyl and C _3-14 alkenyl; each R* is independently selected from the group consisting of Ci-12 alkyl and C2-12 alkenyl; each Y is independently a C _3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

In some embodiments, another subset of compounds of Formula (I) includes those in which

Ri is selected from the group consisting of C _5-30 alkyl, C _5-20 alkenyl, -R*YR”, -YR”, and R”M’R’;

R ₂ and R ₃ are independently selected from the group consisting of H, C _2-14 alkyl, C _2-14 alkenyl, -R*YR”, -YR”, and -R*OR”, or R ₂ and R ₃ , together with the atom to which they are attached, form a heterocycle or carbocycle;

R4 is -(CH ₂ ) _n Q or -(CH ₂ ) _n CHQR, where Q is -N(R) ₂ , and n is selected from 3, 4, and 5; each R ₅ is independently selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H; each R ₆ is independently selected from the group consisting of C _1-3 alkyl, C _2-3 alkenyl, and H; M and M’ are independently selected from -C(0)0-, -OC(O)-, -C(0)N(R’)-,

-N(R’)C(0)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(0)(0R’)0-, -S(0) ₂ -, -S-S-, an aryl group, and a heteroaryl group;

R7 is selected from the group consisting of C1-3 alkyl, C2-3 alkenyl, and H; each R is independently selected from the group consisting of C1-3 alkyl, C2-3 alkenyl, and H; each R’ is independently selected from the group consisting of Ci-is alkyl, C2-18 alkenyl, -R*YR”, -YR”, and H; each R” is independently selected from the group consisting of C3-14 alkyl and C3-14 alkenyl; each R* is independently selected from the group consisting of Ci-12 alkyl and Ci-12 alkenyl; each Y is independently a C3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

In some embodiments, another subset of compounds of Formula (I) includes those in which

Ri is selected from the group consisting of C5-30 alkyl, C5-20 alkenyl, -R*YR”, -YR”, and -R”M’R’;

R2 and R3 are independently selected from the group consisting of Ci-14 alkyl, C2-14 alkenyl, -R*YR”, -YR”, and -R*OR”, or R2 and R3, together with the atom to which they are attached, form a heterocycle or carbocycle;

R4 is selected from the group consisting of -(CH2) _n Q, -(CH2) _n CHQR, -CHQR, and -CQ(R)2, where Q is -N(R) ₂ , and n is selected from 1, 2, 3, 4, and 5; each R ₅ is independently selected from the group consisting of C _1-3 alkyl, C2-3 alkenyl, and H; each R ₆ is independently selected from the group consisting of C1-3 alkyl, C2-3 alkenyl, and H;

M and M’ are independently selected from -C(0)0-, -OC(O)-, -C(0)N(R’)-,

-N(R’)C(0)-, -C(O)-, -C(S)-, -C(S)S-, -SC(S)-, -CH(OH)-, -P(0)(0R’)0-, -S(0) ₂ -, -S-S-, an aryl group, and a heteroaryl group;

R ₇ is selected from the group consisting of C _1-3 alkyl, C2-3 alkenyl, and H; each R is independently selected from the group consisting of C1-3 alkyl, C2-3 alkenyl, and

H; each R’ is independently selected from the group consisting of C1-18 alkyl, C2-18 alkenyl, -R*YR”, -YR”, and H; each R” is independently selected from the group consisting of C3-14 alkyl and C3-14 alkenyl; each R* is independently selected from the group consisting of Ci-12 alkyl and Ci-12 alkenyl; each Y is independently a C3-6 carbocycle; each X is independently selected from the group consisting of F, Cl, Br, and I; and m is selected from 5, 6, 7, 8, 9, 10, 11, 12, and 13, or salts or isomers thereof.

In some embodiments, a subset of compounds of Formula (I) includes those of Formula

(IA): (IA), or a salt or isomer thereof, wherein 1 is selected from 1, 2, 3, 4, and 5; m is selected from 5, 6, 7, 8, and 9; Mi is a bond or M’; R4 is unsubstituted C1-3 alkyl, or -(CH2) _n Q, in which Q is OH, -NHC(S)N(R)2, -NHC(0)N(R)2, -N(R)C(0)R, -N(R)S(0) ₂ R, -N(R)RS, -NHC(=NR ₉ )N(R) ₂ , -NHC(=CHR ₉ )N(R) ₂ , -0C(0)N(R) ₂ , -N(R)C(0)0R, heteroaryl or heterocycloalkyl; M and M’ are independently selected from -C(0)0-, -OC(O)-, -C(0)N(R’)-, -P(0)(0R’)0-, -S-S-, an aryl group, and a heteroaryl group; and R2 and R3 are independently selected from the group consisting of H, Ci-14 alkyl, and C2-14 alkenyl.

In some embodiments, a subset of compounds of Formula (I) includes those of Formula

(II): (II) or a salt or isomer thereof, wherein 1 is selected from 1, 2, 3, 4, and 5; Mi is a bond or M’; R4 is unsubstituted C1-3 alkyl, or -(CH2) _n Q, in which n is 2, 3, or 4, and Q is OH, -NHC(S)N(R) ₂ , -NHC(0)N(R) ₂ , -N(R)C(0)R,

-N(R)S(0) ₂ R, -N(R)RS, -NHC(=NR ₉ )N(R) ₂ , -NHC(=CHR ₉ )N(R) ₂ , -0C(0)N(R)2, -N(R)C(0)0R, heteroaryl or heterocycloalkyl; M and M’ are independently selected from -C(0)0-, -OC(O)-, -C(0)N(R’)-, -P(0)(0R’)0-, -S-S-, an aryl group, and a heteroaryl group; and R2 and R3 are independently selected from the group consisting of H, Ci-14 alkyl, and C2-14 alkenyl. In some embodiments, a subset of compounds of Formula (I) includes those of Formula (Ila), (lib), (lie), or (He): or a salt or isomer thereof, wherein R4 is as described herein.

In some embodiments, a subset of compounds of Formula (I) includes those of Formula

(lid): (lid), or a salt or isomer thereof, wherein n is 2, 3, or 4; and m, R’, R”, and R2 through R ₆ are as described herein. For example, each of R2 and R3 may be independently selected from the group consisting of C5-14 alkyl and C5-14 alkenyl.

In some embodiments, an ionizable amino lipid of the disclosure comprises a compound having structure:

In some embodiments, an ionizable amino lipid of the disclosure comprises a compound having structure:

In some embodiments, a non-cationic lipid of the disclosure comprises 1,2-distearoyl-sn- glycero-3-phosphocholine (DSPC), l,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), l,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLPC), 1,2-dimyristoyl-sn-gly cero- phosphocholine (DMPC), l,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC), 1,2-diundecanoyl-sn-glycero-phosphocholine (DUPC), 1- palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), l,2-di-0-octadecenyl-sn-glycero-3- phosphocholine (18:0 Diether PC), l-oleoyl-2 cholesterylhemisuccinoyl-sn-glycero-3- phosphocholine (OChemsPC), l-hexadecyl-sn-glycero-3-phosphocholine (C16 Lyso PC), 1,2- dilinolenoyl-sn-glycero-3-phosphocholine,l,2-diarachidonoyl- sn-glycero-3-phosphocholine, 1,2- didocosahexaenoyl-sn-glycero-3-phosphocholine, l,2-diphytanoyl-sn-glycero-3- phosphoethanolamine (ME 16.0 PE), l,2-distearoyl-sn-glycero-3-phosphoethanolamine, 1,2- dilinoleoyl-sn-glycero-3-phosphoethanolamine, l,2-dilinolenoyl-sn-glycero-3- phosphoethanolamine, 1 ,2-diarachidonoyl-sn-glycero-3-phosphoethanolamine, 1 ,2- didocosahexaenoyl-sn-glycero-3-phosphoethanolamine, l,2-dioleoyl-sn-glycero-3-phospho-rac- ( 1-glycerol) sodium salt (DOPG), sphingomyelin, and mixtures thereof.

In some embodiments, a PEG modified lipid of the disclosure comprises a PEG-modified phosphatidylethanolamine, a PEG-modified phosphatidic acid, a PEG-modified ceramide, a PEG-modified dialkylamine, a PEG-modified diacylglycerol, a PEG-modified dialkylglycerol, and mixtures thereof. In some embodiments, the PEG-modified lipid is DMG-PEG, PEG-c- DOMG (also referred to as PEG-DOMG), PEG-DSG and/or PEG-DPG.

In some embodiments, a sterol of the disclosure comprises cholesterol, fecosterol, sitosterol, ergosterol, campesterol, stigmasterol, brassicasterol, tomatidine, ursolic acid, alpha- tocopherol, and mixtures thereof. In some embodiments, an LNP of the disclosure comprises an ionizable amino lipid of Compound 1, wherein the non-cationic lipid is DSPC, the structural lipid that is cholesterol, and the PEG lipid is DMG-PEG.

In some embodiments, the lipid nanoparticle comprises 45 - 55 mole percent (mol%) ionizable amino lipid. For example, lipid nanoparticle may comprise 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 mol% ionizable amino lipid.

In some embodiments, the lipid nanoparticle comprises 5 - 15 mol% DSPC. For example, the lipid nanoparticle may comprise 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 mol% DSPC.

In some embodiments, the lipid nanoparticle comprises 35 - 40 mol% cholesterol. For example, the lipid nanoparticle may comprise 35, 36, 37, 38, 39, or 40 mol% cholesterol.

In some embodiments, the lipid nanoparticle comprises 1 - 2 mol% DMG-PEG. For example, the lipid nanoparticle may comprise 1, 1.5, or 2 mol% DMG-PEG.

In some embodiments, the lipid nanoparticle comprises 50 mol% ionizable amino lipid,

10 mol% DSPC, 38.5 mol% cholesterol, and 1.5 mol% DMG-PEG.

In some embodiments, an LNP of the disclosure comprises an N:P ratio of from about 2:1 to about 30:1.

In some embodiments, an LNP of the disclosure comprises an N:P ratio of about 6:1.

In some embodiments, an LNP of the disclosure comprises an N:P ratio of about 3:1.

In some embodiments, an LNP of the disclosure comprises a wt/wt ratio of the ionizable amino lipid component to the RNA of from about 10:1 to about 100:1.

In some embodiments, an LNP of the disclosure comprises a wt/wt ratio of the ionizable amino lipid component to the RNA of about 20:1.

In some embodiments, an LNP of the disclosure comprises a wt/wt ratio of the ionizable amino lipid component to the RNA of about 10:1.

In some embodiments, an LNP of the disclosure has a mean diameter from about 50 nm to about 150 nm.

In some embodiments, an LNP of the disclosure has a mean diameter from about 70 nm to about 120 nm.

Multivalent Vaccines

The compositions ( e.g ., pharmaceutical compositions and/or LNPs), as provided herein, may include RNA or multiple RNAs encoding two or more antigens of the same or different species. In some embodiments, a composition includes an RNA or multiple RNAs encoding two or more coronavims antigens. In some embodiments, the RNA may encode 1, 2, 3, 4, 5, 6, 7, 8,

9, 10, 11, 12, or more coronavims antigens. In some embodiments, two or more different RNA ( e.g ., mRNA) encoding antigens may be formulated in the same lipid nanoparticle. In other embodiments, two or more different RNA encoding antigens may be formulated in separate lipid nanoparticles (each RNA formulated in a single lipid nanoparticle). The lipid nanoparticles may then be combined and administered as a single vaccine composition (e.g., comprising multiple RNA encoding multiple antigens) or may be administered separately.

Combination Vaccines

The compositions, as provided herein, may include an RNA or multiple RNAs encoding two or more antigens of the same or different viral strains. Also provided herein are combination vaccines that include RNA encoding one or more coronavirus and one or more antigen(s) of a different organism. Thus, the vaccines of the present disclosure may be combination vaccines that target one or more antigens of the same strain/species, or one or more antigens of different strains/species, e.g., antigens which induce immunity to organisms which are found in the same geographic areas where the risk of coronavirus infection is high or organisms to which an individual is likely to be exposed to when exposed to a coronavirus.

Pharmaceutical Formulations

Provided herein are compositions (e.g., pharmaceutical compositions), methods, kits and reagents for prevention or treatment of coronavirus in humans and other mammals, for example. The compositions (e.g., mRNA or mRNA formulated in LNP, with or without adjuvant) provided herein can be used as therapeutic or prophylactic agents. They may be used in medicine to prevent and/or treat a coronavirus infection.

In some embodiments, the coronavirus vaccine containing RNA as described herein can be administered to a subject (e.g., a mammalian subject, such as a human subject), and the RNAs are translated in vivo to produce an antigen.

An “effective amount” of a composition (e.g., comprising RNA) is based, at least in part, on the target tissue, target cell type, means of administration, physical characteristics of the RNA (e.g., length, nucleotide composition, and/or extent of modified nucleosides), other components of the vaccine, and other determinants, such as age, body weight, height, sex and general health of the subject. Typically, an effective amount of a composition provides an induced or boosted immune response as a function of antigen production in the cells of the subject. In some embodiments, an effective amount of the composition containing RNAs having at least one chemical modification are more efficient than a composition containing a corresponding unmodified RNA encoding the same antigen or a peptide antigen. Increased antigen production may be demonstrated by increased cell transfection (the percentage of cells transfected with the RNA vaccine), increased protein translation and/or expression from the RNA, decreased nucleic acid degradation (as demonstrated, for example, by increased duration of protein translation from a modified RNA), or altered antigen specific immune response of the host cell.

The term "pharmaceutical composition" refers to the combination of an active agent with a carrier, inert or active, making the composition especially suitable for diagnostic or therapeutic use in vivo or ex vivo. A "pharmaceutically acceptable carrier," after administered to or upon a subject, does not cause undesirable physiological effects. The carrier in the pharmaceutical composition must be "acceptable" also in the sense that it is compatible with the active ingredient and can be capable of stabilizing it. One or more solubilizing agents can be utilized as pharmaceutical carriers for delivery of an active agent. Examples of a pharmaceutically acceptable carrier include, but are not limited to, biocompatible vehicles, adjuvants, additives, and diluents to achieve a composition usable as a dosage form. Examples of other carriers include colloidal silicon oxide, magnesium stearate, cellulose, and sodium lauryl sulfate. Additional suitable pharmaceutical carriers and diluents, as well as pharmaceutical necessities for their use, are described in Remington's Pharmaceutical Sciences.

In some embodiments, the compositions (comprising polynucleotides and their encoded polypeptides) in accordance with the present disclosure may be used for treatment or prevention of a coronavirus infection. A composition may be administered prophylactically or therapeutically as part of an active immunization scheme to healthy individuals or early in infection during the incubation phase or during active infection after onset of symptoms. In some embodiments, the amount of RNA provided to a cell, a tissue or a subject may be an amount effective for immune prophylaxis.

A composition may be administered with other prophylactic or therapeutic compounds.

As a non-limiting example, a prophylactic or therapeutic compound may be an adjuvant or a booster. As used herein, when referring to a prophylactic composition, such as a vaccine, the term “booster” refers to an extra administration of the prophylactic (vaccine) composition. A booster (or booster vaccine) may be given after an earlier administration of the prophylactic composition. The time of administration between the initial administration of the prophylactic composition and the booster may be, but is not limited to, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 15 minutes, 20 minutes 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 1 day, 36 hours, 2 days, 3 days, 4 days, 5 days, 6 days, 1 week, 10 days, 2 weeks, 3 weeks, 1 month, 2 months, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, 10 months, 11 months, 1 year, 18 months, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, 8 years, 9 years, 10 years, 11 years, 12 years, 13 years, 14 years, 15 years, 16 years, 17 years, 18 years, 19 years, 20 years, 25 years, 30 years, 35 years, 40 years, 45 years, 50 years, 55 years, 60 years, 65 years, 70 years, 75 years, 80 years, 85 years, 90 years, 95 years or more than 99 years. In exemplary embodiments, the time of administration between the initial administration of the prophylactic composition and the booster may be, but is not limited to, 1 week, 2 weeks, 3 weeks, 1 month, 2 months, 3 months, 6 months or 1 year.

In some embodiments, a composition may be administered intramuscularly, intranasally or intradermally, similarly to the administration of inactivated vaccines known in the art.

The vaccine may be administered to seropositive or seronegative subjects. For example, a subject may be naive and not have antibodies that react with a virus having an antigen, wherein the antigen is the viral antigen or fragment thereof encoded by the mRNA of the vaccine. Such a subject is said to be seronegative with respect to that vaccine. Alternatively, the subject may have preexisting antibodies to viral antigen encoded by the mRNA of the vaccine because they have previously had an infection with virus carrying the antigen or may have previously been administered a dose of a vaccine (e.g., an mRNA vaccine) that induces antibodies against the antigen. Such a subject is said to be seropositive with respect to that vaccine. In some instances the subject may have been previously exposed to a virus (e.g., SARS-CoV-2) but not to a specific strain of the virus or a specific vaccine associated with that strain or the vaccine of the invention. Such a subject is considered to be seronegative with respect to the specific strain or the specific antigen of the vaccine.

Thus, the present disclosure provides compositions (e.g., mRNA vaccines) that elicit potent neutralizing antibodies against an antigen (e.g., SARS-CoV-2 S protein)_in a subject.

Such a composition can be administered to seropositive or seronegative subjects in some embodiments. A seronegative subject may be naive and not have antibodies that react with the specific virus which the subject is being immunized against. A seropositive subject may have preexisting antibodies to the specific virus because they have previously had an infection with that virus, strain or may have previously been administered a dose of a vaccine (e.g., an mRNA vaccine) that induces antibodies against that virus, strain.

A composition may be utilized in various settings depending on the prevalence of the infection or the degree or level of unmet medical need. As a non-limiting example, the RNA vaccines may be utilized to treat and/or prevent a variety of infectious disease. RNA vaccines have superior properties in that they produce much larger antibody titers, better neutralizing immunity, produce more durable immune responses, and/or produce responses earlier than commercially available vaccines. Provided herein are pharmaceutical compositions including RNA and/or complexes optionally in combination with one or more pharmaceutically acceptable excipients.

The RNA may be formulated or administered alone or in conjunction with one or more other components. For example, a composition may comprise other components including, but not limited to, adjuvants.

In some embodiments, a composition does not include an adjuvant (they are adjuvant free).

An RNA may be formulated or administered in combination with one or more pharmaceutically-acceptable excipients. In some embodiments, vaccine compositions comprise at least one additional active substance, such as, for example, a therapeutically-active substance, a prophylactically-active substance, or a combination of both. Vaccine compositions may be sterile, pyrogen-free or both sterile and pyrogen-free. General considerations in the formulation and/or manufacture of pharmaceutical agents, such as vaccine compositions, may be found, for example, in Remington: The Science and Practice of Pharmacy 21st ed., Lippincott Williams & Wilkins, 2005 (incorporated herein by reference in its entirety).

In some embodiments, a composition is administered to humans, human patients or subjects. For the purposes of the present disclosure, the phrase “active ingredient” generally refers to the RNA, for example, RNAs ( e.g ., mRNAs) encoding antigens.

Formulations of the vaccine compositions described herein may be prepared by any method known or hereafter developed in the art of pharmacology. In general, such preparatory methods include the step of bringing the active ingredient (e.g., mRNA) into association with an excipient and/or one or more other accessory ingredients, and then, if necessary and/or desirable, dividing, shaping and/or packaging the product into a desired single- or multi-dose unit.

Relative amounts of the active ingredient, the pharmaceutically acceptable excipient, and/or any additional ingredients in a pharmaceutical composition in accordance with the disclosure will vary, depending upon the identity, size, and/or condition of the subject treated and further depending upon the route by which the composition is to be administered. By way of example, the composition may comprise between 0.1% and 100%, e.g., between 0.5 and 50%, between 1-30%, between 5-80%, at least 80% (w/w) active ingredient.

In some embodiments, an RNA is formulated using one or more excipients to: (1) increase stability; (2) increase cell transfection; (3) permit the sustained or delayed release (e.g., from a depot formulation); (4) alter the biodistribution (e.g., target to specific tissues or cell types); (5) increase the translation of encoded protein in vivo, and/or (6) alter the release profile of encoded protein (antigen) in vivo. In addition to traditional excipients such as any and all solvents, dispersion media, diluents, or other liquid vehicles, dispersion or suspension aids, surface active agents, isotonic agents, thickening or emulsifying agents, preservatives, excipients can include, without limitation, lipidoids, liposomes, lipid nanoparticles, polymers, lipoplexes, core-shell nanoparticles, peptides, proteins, cells transfected with the RNA (e.g., for transplantation into a subject), hyaluronidase, nanoparticle mimics and combinations thereof.

Dosing/Administration

Provided herein are compositions (e.g., RNA vaccines), methods, kits and reagents for prevention and/or treatment of coronavirus infection in humans and other mammals. Compositions can be used as therapeutic or prophylactic agents. In some embodiments, compositions are used to provide prophylactic protection from coronavirus infection. In some embodiments, compositions are used to treat a coronavirus infection. In some embodiments, embodiments, compositions are used in the priming of immune effector cells, for example, to activate peripheral blood mononuclear cells (PBMCs) ex vivo, which are then infused (re infused) into a subject.

A subject may be any mammal, including non-human primate and human subjects. Typically, a subject is a human subject.

In some embodiments, a composition (e.g., RNA a vaccine) is administered to a subject (e.g., a mammalian subject, such as a human subject) in an effective amount to induce an antigen- specific immune response. The RNA encoding the coronavirus antigen is expressed and translated in vivo to produce the antigen, which then stimulates an immune response in the subject.

Prophylactic protection from a coronavirus can be achieved following administration of a composition (e.g., an RNA vaccine) of the present disclosure. Compositions can be administered once, twice, three times, four times or more but it is likely sufficient to administer the vaccine once (optionally followed by a single booster). It is possible, although less desirable, to administer a composition to an infected individual to achieve a therapeutic response. Dosing may need to be adjusted accordingly.

A method of eliciting an immune response in a subject against a coronavirus antigen (or multiple antigens) is provided in aspects of the present disclosure. In some embodiments, a method involves administering to the subject a composition comprising a RNA (e.g., mRNA) having an open reading frame encoding a coronavirus antigen, thereby inducing in the subject an immune response specific to the coronavirus antigen, wherein anti-antigen antibody titer in the subject is increased following vaccination relative to anti-antigen antibody titer in a subject vaccinated with a prophylactically effective dose of a traditional vaccine against the antigen. An “anti-antigen antibody” is a serum antibody the binds specifically to the antigen. A prophylactically effective dose is an effective dose that prevents infection with the vims at a clinically acceptable level. In some embodiments, the effective dose is a dose listed in a package insert for the vaccine. A traditional vaccine, as used herein, refers to a vaccine other than the mRNA vaccines of the present disclosure. For instance, a traditional vaccine includes, but is not limited, to live microorganism vaccines, killed microorganism vaccines, subunit vaccines, protein antigen vaccines, DNA vaccines, vims like particle (VLP) vaccines, etc. In exemplary embodiments, a traditional vaccine is a vaccine that has achieved regulatory approval and/or is registered by a national drug regulatory body, for example the Food and Drug Administration (FDA) in the United States or the European Medicines Agency (EMA).

In some embodiments, the anti-antigen antibody titer in the subject is increased 1 log to 10 log following vaccination relative to anti-antigen antibody titer in a subject vaccinated with a prophylactically effective dose of a traditional vaccine against the coronavims or an unvaccinated subject. In some embodiments, the anti-antigen antibody titer in the subject is increased 1 log, 2 log, 3 log, 4 log, 5 log, or 10 log following vaccination relative to anti-antigen antibody titer in a subject vaccinated with a prophylactically effective dose of a traditional vaccine against the coronavims or an unvaccinated subject.

A method of eliciting an immune response in a subject against a coronavims is provided in other aspects of the disclosure. The method involves administering to the subject a composition ( e.g ., an RNA vaccine) comprising a RNA comprising an open reading frame encoding a coronavims antigen, thereby inducing in the subject an immune response specific to the coronavims, wherein the immune response in the subject is equivalent to an immune response in a subject vaccinated with a traditional vaccine against the coronavims at 2 times to 100 times the dosage level relative to the composition.

In some embodiments, the immune response in the subject is equivalent to an immune response in a subject vaccinated with a traditional vaccine at twice the dosage level relative to a composition of the present disclosure. In some embodiments, the immune response in the subject is equivalent to an immune response in a subject vaccinated with a traditional vaccine at three times the dosage level relative to a composition of the present disclosure. In some embodiments, the immune response in the subject is equivalent to an immune response in a subject vaccinated with a traditional vaccine at 4 times, 5 times, 10 times, 50 times, or 100 times the dosage level relative to a composition of the present disclosure. In some embodiments, the immune response in the subject is equivalent to an immune response in a subject vaccinated with a traditional vaccine at 10 times to 1000 times the dosage level relative to a composition of the present disclosure. In some embodiments, the immune response in the subject is equivalent to an immune response in a subject vaccinated with a traditional vaccine at 100 times to 1000 times the dosage level relative to a composition of the present disclosure.

In other embodiments, the immune response is assessed by determining [protein] antibody titer in the subject. In other embodiments, the ability of serum or antibody from an immunized subject is tested for its ability to neutralize viral uptake or reduce coronavirus transformation of human B lymphocytes. In other embodiments, the ability to promote a robust T cell response(s) is measured using art recognized techniques.

Other aspects the disclosure provide methods of eliciting an immune response in a subject against a coronavirus by administering to the subject a composition ( e.g ., an RNA vaccine) comprising an RNA having an open reading frame encoding a coronavirus antigen, thereby inducing in the subject an immune response specific to the coronavirus antigen, wherein the immune response in the subject is induced 2 days to 10 weeks earlier relative to an immune response induced in a subject vaccinated with a prophylactically effective dose of a traditional vaccine against the coronavirus. In some embodiments, the immune response in the subject is induced in a subject vaccinated with a prophylactically effective dose of a traditional vaccine at 2 times to 100 times the dosage level relative to a composition of the present disclosure.

In some embodiments, the immune response in the subject is induced 2 days, 3 days, 1 week, 2 weeks, 3 weeks, 5 weeks, or 10 weeks earlier relative to an immune response induced in a subject vaccinated with a prophylactically effective dose of a traditional vaccine.

Also provided herein are methods of eliciting an immune response in a subject against a coronavirus by administering to the subject an RNA having an open reading frame encoding a first antigen, wherein the RNA does not include a stabilization element, and wherein an adjuvant is not co-formulated or co-administered with the vaccine.

A composition (e.g., an RNA vaccine) may be administered by any route that results in a therapeutically effective outcome. These include, but are not limited, to intradermal, intramuscular, intranasal, and/or subcutaneous administration. The present disclosure provides methods comprising administering RNA vaccines to a subject in need thereof. The exact amount required will vary from subject to subject, depending on the species, age, and general condition of the subject, the severity of the disease, the particular composition, its mode of administration, its mode of activity, and the like. The RNA is typically formulated in dosage unit form for ease of administration and uniformity of dosage. It will be understood, however, that the total daily usage of the RNA may be decided by the attending physician within the scope of sound medical judgment. The specific therapeutically effective, prophylactically effective, or appropriate imaging dose level for any particular patient will depend upon a variety of factors including the disorder being treated and the severity of the disorder; the activity of the specific compound employed; the specific composition employed; the age, body weight, general health, sex and diet of the patient; the time of administration, route of administration, and rate of excretion of the specific compound employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed; and like factors well known in the medical arts.

The effective amount of the RNA, as provided herein, may be as low as 20 pg, administered for example as a single dose or as two 10 pg doses. In some embodiments, the effective amount is a total dose of 20 pg-300 pg or 25 pg-300 pg. For example, the effective amount may be a total dose of 20 pg, 25 pg, 30 pg, 35 pg, 40 pg, 45 pg, 50 pg, 55 pg, 60 pg, 65 pg, 70 pg, 75 pg, 80 pg, 85 pg, 90 pg, 95 pg, 100 pg, 110 pg, 120 pg, 130 pg, 140 pg, 150 pg, 160 pg, 170 pg, 180 pg, 190 pg, 200 pg, 250 pg, or 300 pg. In some embodiments, the effective amount is a total dose of 20 pg. In some embodiments, the effective amount is a total dose of 25 pg. In some embodiments, the effective amount is a total dose of 75 pg. In some embodiments, the effective amount is a total dose of 150 pg. In some embodiments, the effective amount is a total dose of 300 pg.

The RNA described herein can be formulated into a dosage form described herein, such as an intranasal, intratracheal, or injectable ( e.g ., intravenous, intraocular, intravitreal, intramuscular, intradermal, intracardiac, intraperitoneal, and subcutaneous).

Vaccine Efficacy

Some aspects of the present disclosure provide formulations of the compositions (e.g., RNA vaccines), wherein the RNA is formulated in an effective amount to produce an antigen specific immune response in a subject (e.g., production of antibodies specific to a coronavims antigen). “An effective amount” is a dose of the RNA effective to produce an antigen- specific immune response. Also provided herein are methods of inducing an antigen-specific immune response in a subject.

As used herein, an immune response to a vaccine or LNP of the present disclosure is the development in a subject of a humoral and/or a cellular immune response to a (one or more) coronavims protein(s) present in the vaccine. For purposes of the present disclosure, a “humoral” immune response refers to an immune response mediated by antibody molecules, including, e.g., secretory (IgA) or IgG molecules, while a “cellular” immune response is one mediated by T- lymphocytes (e.g., CD4+ helper and/or CD8+ T cells (e.g., CTLs) and/or other white blood cells. One important aspect of cellular immunity involves an antigen- specific response by cytolytic T- cells (CTLs). CTLs have specificity for peptide antigens that are presented in association with proteins encoded by the major histocompatibility complex (MHC) and expressed on the surfaces of cells. CTLs help induce and promote the destruction of intracellular microbes or the lysis of cells infected with such microbes. Another aspect of cellular immunity involves and antigen- specific response by helper T-cells. Helper T-cells act to help stimulate the function, and focus the activity nonspecific effector cells against cells displaying peptide antigens in association with MHC molecules on their surface. A cellular immune response also leads to the production of cytokines, chemokines, and other such molecules produced by activated T-cells and/or other white blood cells including those derived from CD4+ and CD8+ T-cells.

In some embodiments, the antigen- specific immune response is characterized by measuring an anti-coronavims antigen antibody titer produced in a subject administered a composition as provided herein. An antibody titer is a measurement of the number of antibodies within a subject, for example, antibodies that are specific to a particular antigen or epitope of an antigen. Antibody titer is typically expressed as the inverse of the greatest dilution that provides a positive result. Enzyme-linked immunosorbent assay (ELISA) is a common assay for determining antibody titers, for example.

In some embodiments, an antibody titer is used to assess whether a subject has had an infection or to determine whether immunizations are required. In some embodiments, an antibody titer is used to determine the strength of an autoimmune response, to determine whether a booster immunization is needed, to determine whether a previous vaccine was effective, and to identify any recent or prior infections. In accordance with the present disclosure, an antibody titer may be used to determine the strength of an immune response induced in a subject by a composition (e.g., RNA vaccine).

In some embodiments, an anti-coronavirus antigen antibody titer produced in a subject is increased by at least 1 log relative to a control. For example, anti-coronavirus antigen antibody titer produced in a subject may be increased by at least 1.5, at least 2, at least 2.5, or at least 3 log relative to a control. In some embodiments, the anti-coronavims antigen antibody titer produced in the subject is increased by 1, 1.5, 2, 2.5 or 3 log relative to a control. In some embodiments, the anti-coronavims antigen antibody titer produced in the subject is increased by 1-3 log relative to a control. For example, the anti-coronavims antigen antibody titer produced in a subject may be increased by 1-1.5, 1-2, 1-2.5, 1-3, 1.5-2, 1.5-2.5, 1.5-3, 2-2.5, 2-3, or 2.5-3 log relative to a control.

In some embodiments, the anti-coronavims antigen antibody titer produced in a subject is increased at least 2 times relative to a control. For example, the anti-coronavims antigen n antibody titer produced in a subject may be increased at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, or at least 10 times relative to a control. In some embodiments, the anti-coronavims antigen antibody titer produced in the subject is increased 2, 3, 4, 5, 6, 7, 8, 9, or 10 times relative to a control. In some embodiments, the anti-coronavirus antigen antibody titer produced in a subject is increased 2-10 times relative to a control. For example, the anti-coronavirus antigen antibody titer produced in a subject may be increased 2-10, 2-9, 2-8, 2-7, 2-6, 2-5, 2-4, 2-3, 3-10, 3-9, 3-8, 3-7, 3-6, 3-5, 3-4, 4-10, 4-9, 4-8, 4-7, 4-6, 4-5, 5-10, 5-9, 5-8, 5-7, 5-6, 6-10, 6-9, 6-8, 6-7, 7-10, 7-9, 7-8, 8-10, 8-9, or 9-10 times relative to a control.

In some embodiments, an antigen- specific immune response is measured as a ratio of geometric mean titer (GMT), referred to as a geometric mean ratio (GMR), of serum neutralizing antibody titers to coronavirus. A geometric mean titer (GMT) is the average antibody titer for a group of subjects calculated by multiplying all values and taking the nth root of the number, where n is the number of subjects with available data.

A control, in some embodiments, is an anti-coronavirus antigen antibody titer produced in a subject who has not been administered a composition ( e.g ., RNA vaccine). In some embodiments, a control is an anti-coronavirus antigen antibody titer produced in a subject administered a recombinant or purified protein vaccine. Recombinant protein vaccines typically include protein antigens that either have been produced in a heterologous expression system (e.g., bacteria or yeast) or purified from large amounts of the pathogenic organism.

In some embodiments, the ability of a composition (e.g., RNA vaccine) to be effective is measured in a murine model. For example, a composition may be administered to a murine model and the murine model assayed for induction of neutralizing antibody titers. Viral challenge studies may also be used to assess the efficacy of a vaccine of the present disclosure. For example, a composition may be administered to a murine model, the murine model challenged with virus, and the murine model assayed for survival and/or immune response (e.g., neutralizing antibody response, T cell response (e.g., cytokine response)).

In some embodiments, an effective amount of a composition (e.g., RNA vaccine) is a dose that is reduced compared to the standard of care dose of a recombinant protein vaccine. A “standard of care,” as provided herein, refers to a medical or psychological treatment guideline and can be general or specific. “Standard of care” specifies appropriate treatment based on scientific evidence and collaboration between medical professionals involved in the treatment of a given condition. It is the diagnostic and treatment process that a physician/ clinician should follow for a certain type of patient, illness or clinical circumstance. A “standard of care dose,” as provided herein, refers to the dose of a recombinant or purified protein vaccine, or a live attenuated or inactivated vaccine, or a VLP vaccine, that a physician/clinician or other medical professional would administer to a subject to treat or prevent coronavirus infection or a related condition, while following the standard of care guideline for treating or preventing coronavirus infection or a related condition. In some embodiments, the anti-coronavirus antigen antibody titer produced in a subject administered an effective amount of a composition is equivalent to an anti-coronavirus antigen antibody titer produced in a control subject administered a standard of care dose of a recombinant or purified protein vaccine, or a live attenuated or inactivated vaccine, or a VLP vaccine.

Vaccine efficacy may be assessed using standard analyses (see, e.g., Weinberg et al., J Infect Dis. 2010 Jun 1 ;201(11): 1607-10). For example, vaccine efficacy may be measured by double-blind, randomized, clinical controlled trials. Vaccine efficacy may be expressed as a proportionate reduction in disease attack rate (AR) between the unvaccinated (ARU) and vaccinated (ARV) study cohorts and can be calculated from the relative risk (RR) of disease among the vaccinated group with use of the following formulas:

Efficacy = (ARU - ARV)/ARU x 100; and

Efficacy = (1-RR) x 100.

Likewise, vaccine effectiveness may be assessed using standard analyses (see, e.g., Weinberg et al., J Infect Dis. 2010 Jun 1 ;201(11): 1607-10). Vaccine effectiveness is an assessment of how a vaccine (which may have already proven to have high vaccine efficacy) reduces disease in a population. This measure can assess the net balance of benefits and adverse effects of a vaccination program, not just the vaccine itself, under natural field conditions rather than in a controlled clinical trial. Vaccine effectiveness is proportional to vaccine efficacy (potency) but is also affected by how well target groups in the population are immunized, as well as by other non-vaccine -related factors that influence the ‘real- world’ outcomes of hospitalizations, ambulatory visits, or costs. For example, a retrospective case control analysis may be used, in which the rates of vaccination among a set of infected cases and appropriate controls are compared. Vaccine effectiveness may be expressed as a rate difference, with use of the odds ratio (OR) for developing infection despite vaccination:

Effectiveness = (1 - OR) x 100.

In some embodiments, efficacy of the composition (e.g., RNA vaccine) is at least 60% relative to unvaccinated control subjects. For example, efficacy of the composition may be at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 95%, at least 98%, or 100% relative to unvaccinated control subjects.

Sterilizing Immunity. Sterilizing immunity refers to a unique immune status that prevents effective pathogen infection into the host. In some embodiments, the effective amount of a composition of the present disclosure is sufficient to provide sterilizing immunity in the subject for at least 1 year. For example, the effective amount of a composition of the present disclosure is sufficient to provide sterilizing immunity in the subject for at least 2 years, at least 3 years, at least 4 years, or at least 5 years. In some embodiments, the effective amount of a composition of the present disclosure is sufficient to provide sterilizing immunity in the subject at an at least 5- fold lower dose relative to control. For example, the effective amount may be sufficient to provide sterilizing immunity in the subject at an at least 10-fold lower, 15-fold, or 20-fold lower dose relative to a control.

Detectable Antigen. In some embodiments, the effective amount of a composition of the present disclosure is sufficient to produce detectable levels of coronavims antigen as measured in serum of the subject at 1-72 hours post administration.

Titer. An antibody titer is a measurement of the number of antibodies within a subject, for example, antibodies that are specific to a particular antigen ( e.g ., an anti-coronavims antigen). Antibody titer is typically expressed as the inverse of the greatest dilution that provides a positive result. Enzyme-linked immunosorbent assay (ELISA) is a common assay for determining antibody titers, for example.

In some embodiments, the effective amount of a composition of the present disclosure is sufficient to produce a 1,000-10,000 neutralizing antibody titer produced by neutralizing antibody against the coronavims antigen as measured in serum of the subject at 1-72 hours post administration. In some embodiments, the effective amount is sufficient to produce a 1,000-5,000 neutralizing antibody titer produced by neutralizing antibody against the coronavims antigen as measured in semm of the subject at 1-72 hours post administration. In some embodiments, the effective amount is sufficient to produce a 5,000-10,000 neutralizing antibody titer produced by neutralizing antibody against the coronavims antigen as measured in semm of the subject at 1-72 hours post administration.

In some embodiments, the neutralizing antibody titer is at least 100 NT50. For example, the neutralizing antibody titer may be at least 200, 300, 400, 500, 600, 700, 800, 900 or 1000 NT50. In some embodiments, the neutralizing antibody titer is at least 10,000 NT50.

In some embodiments, the neutralizing antibody titer is at least 100 neutralizing units per milliliter (NU/mL). For example, the neutralizing antibody titer may be at least 200, 300, 400, 500, 600, 700, 800, 900 or 1000 NU/mL. In some embodiments, the neutralizing antibody titer is at least 10,000 NU/mL.

In some embodiments, an anti-coronavims antigen antibody titer produced in the subject is increased by at least 1 log relative to a control. For example, an anti-coronavims antigen antibody titer produced in the subject may be increased by at least 2, 3, 4, 5, 6, 7, 8, 9 or 10 log relative to a control.

In some embodiments, an anti-coronavims antigen antibody titer produced in the subject is increased at least 2 times relative to a control. For example, an anti-coronavims antigen antibody titer produced in the subject is increased by at least 3, 4, 5, 6, 7, 8, 9 or 10 times relative to a control.

In some embodiments, a geometric mean, which is the nth root of the product of n numbers, is generally used to describe proportional growth. Geometric mean, in some embodiments, is used to characterize antibody titer produced in a subject.

A control may be, for example, an unvaccinated subject, or a subject administered a live attenuated viral vaccine, an inactivated viral vaccine, or a protein subunit vaccine.

EXAMPLES

Example 1- SARS-CoV2 mRNA Vaccine Immunogenicity

B ALB/c mice, 6-8 weeks of age, were administered either 0.1 pg or 1 pg of mRNA encoding a SARS-CoV-2 antigen or PBS (as a control) intramuscularly in one hind leg (formulated as a 50 pL dose) on day 1 and day 22 (n = 8 mice per group). The mRNA tested encoded Spike protein with four glycine substitutions (WH02020_NatSP_4G_RRAR_GSGG- dl3; SEQ ID NO: 6). In the vaccine, the mRNA was formulated in lipid nanoparticles (LNPs) including 0.5-15% PEG-modified lipid, 5-25% non-cationic lipid, 25-55% sterol, and 20-60% ionizable cationic lipid. The PEG-modified lipid was 1,2 dimyristoyl-sn-glycerol, methoxypolyethyleneglycol (PEG2000 DMG), the non-cationic lipid was 1,2 distearoyl-sn- glycero-3-phosphocholine (DSPC), the sterol was cholesterol, and the ionizable cationic lipid had the structure of Compound 1, for example.

Sera of immunized mice were collected at day 15 post- administration of a first dose, and day 36 post-administration of a second dose, and evaluated by ELISA to quantify titers of IgG specific to 2P-stabilized SARS-CoV-2 Spike protein (FIG. 1). Relative to PBS, the SARS-CoV-2 mRNA vaccine formulation elicited increased titers, but the effect was found to be dose- dependent only with the Day 36 group. Increased S-2P binding titers were measured after the second dose (day 36) in both groups. These results demonstrate that both doses of the SARS- CoV-2 mRNA vaccine formulation were active and immunogenic.

SEQUENCE LISTING

Table 1.

* Any one of the open reading frames and/or corresponding amino acid sequences described in Table 1 may include or exclude the signal sequence. It should also be understood that the signal sequence may be replaced by a different signal sequence. Any of the mRNA sequences described herein may include a 5' UTR and/or a 3' UTR.

The UTR sequences may be selected from the following sequences, or other known UTR sequences may be used. It should also be understood that any of the mRNAs described herein may further comprise a poly(A) tail and/or cap ( e.g ., 7mG(5’)ppp(5’)NlmpNp). Further, while many of the mRNAs and encoded antigen sequences described herein include a signal peptide and/or a peptide tag (e.g., C-terminal His tag), it should be understood that the indicated signal peptide and/or peptide tag may be substituted for a different signal peptide and/or peptide tag, or the signal peptide and/or peptide tag may be omitted. 5’ UTR: GGGAAAU AAGAGAGAAAAGAAGAGU AAGAAGAAAU AU AAGAGC C AC C (SEQ ID NO: 12)

5’ UTR: GGGAAAU AAGAGAGAAAAGAAGAGUAAGAAGAAAU AUAAGAC CCCGGCGCC GC C AC C (SEQ ID NO: 2)

3’ UTR: UGAUAAUAGGCUGGAGCCUCGGUGGCCAUGCUUCUUGCCCCUUGGGCCUCCCCCCAGCC CCUCCUCCCCUUCCUGCACCCGUACCCCCGUGGUCUUUGAAUAAAGUCUGAGUGGGCGGC (SEQ ID NO: 13)

3’ UTR: UGAUAAUAGGCUGGAGCCUCGGUGGCCUAGCUUCUUGCCCCUUGGGCCUCCCCCCAGCC CCUCCUCCCCUUCCUGCACCCGUACCCCCGUGGUCUUUGAAUAAAGUCUGAGUGGGCGGC (SEQ ID NO: 4)

SARS-CoV-2 Wuhan-Hu-1 (USA-WA1/2020 isolate ) Spike (S) Protein - SEQ ID NO: 15

MFVFLVLLPLVSSQCVNLTTRTQLPPAYTNSFTRGVYYPDKVFRSSVLHSTQDLFLP FFSNVTWFHAIHVSGTNGTKR FDNPVLPFNDGVYFASTEKSNI IRGWIFGTTLDSKTQSLLIVNNATNWIKVCEFQFCNDPFLGVYYHKNNKSWMESE FRVYSSANNCTFEYVSQPFLMDLEGKQGNFKNLREFVFKNIDGYFKI YSKHTP INLVRDLPQGFSALEPLVDLP IGIN ITRFQTLLALHRSYLTPGDSSSGWTAGAAAYYVGYLQPRTFLLKYNENGTITDAVDCALD PLSETKCTLKSFTVEKGI YQTSNFRVQPTES IVRFPNITNLCPFGEVFNATRFASVYAWNRKRI SNCVADYSVLYNSASFSTFKCYGVSPTKLNDL CFTNVYADSFVIRGDEVRQIAPGQTGKIADYNYKLPDDFTGCVIAWNSNNLDSKVGGNYN YLYRLFRKSNLKPFERDI STEI YQAGSTPCNGVEGFNCYFPLQSYGFQPTNGVGYQPYRVWLSFELLHAPATVCGPKKSTNL VKNKCVNFNFNGL TGTGVLTESNKKFLPFQQFGRDIADTTDAVRDPQTLEILDITPCSFGGVSVITPGTNTSN QVAVLYQDVNCTEVPVAI HADQLTPTWRVYSTGSNVFQTRAGCLIGAEHVNNSYECDIP IGAGICASYQTQTNSPRRARSVASQS I IAYTMSLGAE NSVAYSNNS IAIPTNFTI SVTTEILPVSMTKTSVDCTMYICGDSTECSNLLLQYGSFCTQLNRALTGIAVEQDKNTQE VFAQVKQIYKTPP IKDFGGFNFSQILPDPSKPSKRSFIEDLLFNKVTLADAGFIKQYGDCLGDIAARDLICAQ KFNGL TVLPPLLTDEMIAQYTSALLAGTITSGWTFGAGAALQIPFAMQMAYRFNGIGVTQNVLYE NQKLIANQFNSAIGKIQD SLSSTASALGKLQDWNQNAQALNTLVKQLSSNFGAI SSVLNDILSRLDKVEAEVQIDRLITGRLQSLQTYVTQQLIR AAEIRASANLAATKMSECVLGQSKRVDFCGKGYHLMSFPQSAPHGWFLHVTYVPAQEKNF TTAPAICHDGKAHFPRE GVFVSNGTHWFVTQRNFYEPQI ITTDNTFVSGNCDWIGIVNNTVYDPLQPELDSFKEELDKYFKNHTSPDVDLGDI S GINAS WNIQKEIDRLNEVAKNLNESLIDLQELGKYEQYIKWPWYIWLGFIAGLIAIVMVTIMLCC MTSCCSCLKGCC SCGSCCKFDEDDSEPVLKGVKLHYT

SARS-CoV Spike (S) Protein RNA Coding Sequence - SEQ ID NO: 16 Accession No. AY323976.1

AUGUUUAUUUUCUUAUUAUUUCUUACUCUCACUAGUGGUAGUGACCUUGACCGGUGC ACCACUUUUGAUGAUGUUCAA

GCUCCUAAUUACACUCAACAUACUUCAUCUAUGAGGGGGGUUUACUAUCCUGAUGAA AUUUUUAGAUCAGACACUCUU

UAUUUAACUCAGGAUUUAUUUCUUCCAUUUUAUUCUAAUGUUACAGGGUUUCAUACU AUUAAUCAUACGUUUGGCAAC

CCUGUCAUACCUUUUAAGGAUGGUAUUUAUUUUGCUGCCACAGAGAAAUCAAAUGUU GUCCGUGGUUGGGUUUUUGGU

UCUACCAUGAACAACAAGUCACAGUCGGUGAUUAUUAUUAACAAUUCUACUAAUGUU GUUAUACGAGCAUGUAACUUU

GAAUUGUGUGACAACCCUUUCUUUGCUGUUUCUAAACCCAUGGGUACACAGACACAU ACUAUGAUAUUCGAUAAUGCA

UUUAAUUGCACUUUCGAGUACAUAUCUGAUGCCUUUUCGCUUGAUGUUUCAGAAAAG UCAGGUAAUUUUAAACACUUA

CGAGAGUUUGUGUUUAAAAAUAAAGAUGGGUUUCUCUAUGUUUAUAAGGGCUAUCAA CCUAUAGAUGUAGUUCGUGAU

CUACCUUCUGGUUUUAACACUUUGAAACCUAUUUUUAAGUUGCCUCUUGGUAUUAAC AUUACAAAUUUUAGAGCCAUU

CUUACAGCCUUUUCACCUGCUCAAGACAUUUGGGGCACGUCAGCUGCAGCCUAUUUU GUUGGCUAUUUAAAGCCAACU

ACAUUUAUGCUCAAGUAUGAUGAAAAUGGUACAAUCACAGAUGCUGUUGAUUGUUCU CAAAAUCCACUUGCUGAACUC

AAAUGCUCUGUUAAGAGCUUUGAGAUUGACAAAGGAAUUUACCAGACCUCUAAUUUC AGGGUUGUUCCCUCAGGAGAU

GUUGUGAGAUUCCCUAAUAUUACAAACUUGUGUCCUUUUGGAGAGGUUUUUAAUGCU ACUAAAUUCCCUUCUGUCUAU

GCAUGGGAGAGAAAAAAAAUUUCUAAUUGUGUUGCUGAUUACUCUGUGCUCUACAAC UCAACAUUUUUUUCAACCUUU

AAGUGUUAUGGCGUUUCUGCCACUAAGUUGAAUGAUCUUUGCUUCUCCAAUGUCUAU GCAGAUUCUUUUGUAGUCAAG

GGAGAUGAUGUAAGACAAAUAGCGCCAGGACAAACUGGUGUUAUUGCUGAUUAUAAU UAUAAAUUGCCAGAUGAUUUC

AUGGGUUGUGUCCUUGCUUGGAAUACUAGGAACAUUGAUGCUACUUCAACUGGUAAU UAUAAUUAUAAAUAUAGGUAU

CUUAGACAUGGCAAGCUUAGGCCCUUUGAGAGAGACAUAUCUAAUGUGCCUUUCUCC CCUGAUGGCAAACCUUGCACC

CCACCUGCUCUUAAUUGUUAUUGGCCAUUAAAUGAUUAUGGUUUUUACACCACUACU GGCAUUGGCUACCAACCUUAC

AGAGUUGUAGUACUUUCUUUUGAACUUUUAAAUGCACCGGCCACGGUUUGUGGACCA AAAUUAUCCACUGACCUUAUU

AAGAACCAGUGUGUCAAUUUUAAUUUUAAUGGACUCACUGGUACUGGUGUGUUAACU CCUUCUUCAAAGAGAUUUCAA

CCAUUUCAACAAUUUGGCCGUGAUGUUUCUGAUUUCACUGAUUCCGUUCGAGAUCCU AAAACAUCUGAAAUAUUAGAC

AUUUCACCUUGCUCUUUUGGGGGUGUAAGUGUAAUUACACCUGGAACAAAUGCUUCA UCUGAAGUUGCUGUUCUAUAU

CAAGAUGUUAACUGCACUGAUGUUUCUACAGCAAUUCAUGCAGAUCAACUCACACCA GCUUGGCGCAUAUAUUCUACU

GGAAACAAUGUAUUCCAGACUCAAGCAGGCUGUCUUAUAGGAGCUGAGCAUGUCGAC ACUUCUUAUGAGUGCGACAUU

CCUAUUGGAGCUGGCAUUUGUGCUAGUUACCAUACAGUUUCUUUAUUACGUAGUACU AGCCAAAAAUCUAUUGUGGCU UAUACUAUGUCUUUAGGUGCUGAUAGUUCAAUUGCUUACUCUAAUAACACCAUUGCUAUA CCUACUAACUUUUCAAUU AGCAUUACUACAGAAGUAAUGCCUGUUUCUAUGGCUAAAACCUCCGUAGAUUGUAAUAUG UACAUCUGCGGAGAUUCU ACUGAAUGUGCUAAUUUGCUUCUCCAAUAUGGUAGCUUUUGCACACAACUAAAUCGUGCA CUCUCAGGUAUUGCUGCU GAACAGGAUCGCAACACACGUGAAGUGUUCGCUCAAGUCAAACAAAUGUACAAAACCCCA ACUUUGAAAUAUUUUGGU GGUUUUAAUUUUUCACAAAUAUUACCUGACCCUCUAAAGCCAACUAAGAGGUCUUUUAUU GAGGACUUGCUCUUUAAU AAGGU GAC AC UC GC U GAU GC U GGC UUC AU GAAGC AAU AU GGC GAAU GC C U AGGU GAU AUU AAU GC U AGAGAU C U C AUU UGUGCGCAGAAGUUCAAUGGACUUACAGUGUUGCCACCUCUGCUCACUGAUGAUAUGAUU GCUGCCUACACUGCUGCU CUAGUUAGUGGUACUGCCACUGCUGGAUGGACAUUUGGUGCUGGCGCUGCUCUUCAAAUA CCUUUUGCUAUGCAAAUG GCAUAUAGGUUCAAUGGCAUUGGAGUUACCCAAAAUGUUCUCUAUGAGAACCAAAAACAA AUCGCCAACCAAUUUAAC AAGGCGAUUAGUCAAAUUCAAGAAUCACUUACAACAACAUCAACUGCAUUGGGCAAGCUG CAAGACGUUGUUAACCAG AAUGCUCAAGCAUUAAACACACUUGUUAAACAACUUAGCUCUAAUUUUGGUGCAAUUUCA AGUGUGCUAAAUGAUAUC CUUUCGCGACUUGAUAAAGUCGAGGCGGAGGUACAAAUUGACAGGUUAAUUACAGGCAGA CUUCAAAGCCUUCAAACC UAUGUAACACAACAACUAAUCAGGGCUGCUGAAAUCAGGGCUUCUGCUAAUCUUGCUGCU ACUAAAAUGUCUGAGUGU GUUCUUGGACAAUCAAAAAGAGUUGACUUUUGUGGAAAGGGCUACCACCUUAUGUCCUUC CCACAAGCAGCCCCGCAU GGUGUUGUCUUCCUACAUGUCACGUAUGUGCCAUCCCAGGAGAGGAACUUCACCACAGCG CCAGCAAUUUGUCAUGAA GGCAAAGCAUACUUCCCUCGUGAAGGUGUUUUUGUGUUUAAUGGCACUUCUUGGUUUAUU ACACAGAGGAACUUCUUU UCUCCACAAAUAAUUACUACAGACAAUACAUUUGUCUCAGGAAAUUGUGAUGUCGUUAUU GGCAUCAUUAACAACACA GUUUAUGAUCCUCUGCAACCUGAGCUUGACUCAUUCAAAGAAGAGCUGGACAAGUACUUC AAAAAUCAUACAUCACCA GAUGUUGAUCUUGGCGACAUUUCAGGCAUUAACGCUUCUGUCGUCAACAUUCAAAAAGAA AUUGACCGCCUCAAUGAG GUCGCUAAAAAUUUAAAUGAAUCACUCAUUGACCUUCAAGAAUUGGGAAAAUAUGAGCAA UAUAUUAAAUGGCCUUGG UAUGUUUGGCUCGGCUUCAUUGCUGGACUAAUUGCCAUCGUCAUGGUUACAAUCUUGCUU UGUUGCAUGACUAGUUGU UGCAGUUGCCUCAAGGGUGCAUGCUCUUGUGGUUCUUGCUGCAAGUUUGAUGAGGAUGAC UCUGAGCCAGUUCUCAAG GGUGUCAAAUUACAUUACACAUAA

SARS-CoV Spike (S) Protein Amino Acid Sequence- SEQ ID NO: 17 Accession No. AAP73417.1

MF IFLLFLTLTSGSDLDRCTTFDDVQAPNYTQHTS SMRGVYYPDE IFRSDTLYLTQDLFLPFYSNVTGFHT INHTFGN PVIPFKDGI YFAATEKSNWRGWVFGSTMNNKSQSVI I INNSTNWIRACNFELCDNPFFAVSKPMGTQTHTMIFDNA FNCTFEYI SDAFSLDVSEKSGNFKHLREFVFKNKDGFLYVYKGYQP IDWRDLP SGFNTLKP IFKLPLGINI TNFRAI LTAFSPAQD IWGTSAAAYFVGYLKPTTFMLKYDENGT I TDAVDCSQNPLAELKCSVKSFE IDKGIYQTSNFRWP SGD WRFPNI TNLCPFGEVFNATKFP SVYAWERKKI SNCVADYSVLYNSTFFSTFKCYGVSATKLNDLCFSNVYADSFWK GDDVRQIAPGQTGVIADYNYKLPDDFMGCVLAWNTRNIDATSTGNYNYKYRYLRHGKLRP FERD I SNVPFSPDGKPCT PPALNCYWPLNDYGFYTTTGIGYQPYRVWLSFELLNAPATVCGPKLSTDLIKNQCVNFNF NGLTGTGVLTP S SKRFQ PFQQFGRDVSDFTDSVRDPKTSE ILD I SPCSFGGVSVI TPGTNAS SEVAVLYQDVNCTDVSTAIHADQLTPAWRIYST GNNVFQTQAGCLIGAEHVDTSYECD IP IGAGICASYHTVSLLRSTSQKS IVAYTMSLGADS S IAYSNNT IAIPTNFS I S I TTEVMPVSMAKTSVDCNMYICGDSTECANLLLQYGSFCTQLNRALSGIAAEQDRNTREVF AQVKQMYKTPTLKYFG GFNFSQILPDPLKPTKRSF IEDLLFNKVTLADAGFMKQYGECLGD INARDLICAQKFNGLTVLPPLLTDDMIAAYTAA LVSGTATAGWTFGAGAALQIPFAMQMAYRFNGIGVTQNVLYENQKQIANQFNKAI SQIQESLTTTSTALGKLQDWNQ NAQALNTLVKQLS SNFGAI S SVLND ILSRLDKVEAEVQIDRLI TGRLQSLQTYVTQQLIRAAE IRASANLAATKMSEC VLGQSKRVDFCGKGYHLMSFPQAAPHGWFLHVTYVP SQERNFTTAPAICHEGKAYFPREGVFVFNGTSWF I TQRNFF SPQI I TTDNTFVSGNCDWIGI INNTVYDPLQPELDSFKEELDKYFKNHTSPDVDLGD I SGINASWNIQKE IDRLNE VAKNLNESLIDLQELGKYEQYIKWPWYVWLGF IAGLIAIVMVT ILLCCMTSCCSCLKGACSCGSCCKFDEDDSEPVLK GVKLHYT

MERS-CoV Spike (S) Protein RNA Coding Sequence - SEQ ID NO: 18 Accession No. KF186564.1

AUGAUACACUCAGUGUUUCUACUGAUGUUCUUGUUAACACCUACAGAAAGUUACGUU GAUGUAGGGCCAGAUUCUGUU

AAGUCUGCUUGUAUUGAGGUUGAUAUACAACAGACUUUCUUUGAUAAAACUUGGCCU AGGCCAAUUGAUGUUUCUAAG

GCUGACGGUAUUAUAUACCCUCAAGGCCGUACAUAUUCUAACAUAACUAUCACUUAU CAAGGUCUUUUUCCCUAUCAG

GGAGACCAUGGUGAUAUGUAUGUUUACUCUGCAGGACAUGCUACAGGCACAACUCCA CAAAAGUUGUUUGUAGCUAAC

UAUUCUCAGGACGUCAAACAGUUCGCUAAUGGGUUUGUCGUCCGUAUAGGAGCAGCU GCCAAUUCCACUGGCACUGUU

AUUAUUAGCCCAUCUACCAGCGCUACUAUACGAAAAAUUUACCCUGCUUUUAUGCUG GGUUCUUCAGUUGGUAAUUUC

UCAGAUGGUAAAAUGGGCCGCUUCUUCAAUCAUACUCUAGUCCUUUUGCCCGAUGGA UGUGGCACUUUACUUAGAGCU

UUUUAUUGUAUUCUAGAGCCUCGCUCUGGAAAUCAUUGUCCUGCUGGCAAUUCCUAU ACUUCUUUUGCCACUUAUCAC

ACUCCUGCAACAGAUUGUUCUGAUGGCAAUUACAAUCGUAAUGCCAGUCUGAACUCU UUUAAGGAGUAUUUUAAUUUA

CGUAACUGCACCUUUAUGUACACUUAUAACAUUACCGAAGAUGAGAUUUUAGAGUGG UUUGGCAUUACACAAACUGCU

CAAGGUGUUCACCUCUUCUCAUCUCGGUAUGUUGAUUUGUACGGCGGCAAUAUGUUU CAAUUUGCCACCUUGCCUGUU UAUGAUACUAUUAAGUAUUACUCUAUCAUUCCUCACAGUAUUCGUUCUAUCCAAAGUGAU AGAAAAGCUUGGGCUGCC

UUCUACGUAUAUAAACUUCAACCGUUAACUUUCCUGUUGGAUUUUUCUGUUGAUGGU UAUAUACGCAGAGCUAUAGAC

UGUGGUUUUAAUGAUUUGUCACAACUCCACUGCUCAUAUGAAUCCUUCGAUGUUGAA UCUGGAGUUUAUUCAGUUUCG

UCUUUCGAAGCAAAACCUUCUGGCUCAGUUGUGGAACAGGCUGAAGGUGUUGAAUGU GAUUUUUCACCUCUUCUGUCU

GGCACACCUCCUCAGGUUUAUAAUUUCAAGCGUUUGGUUUUUACCAAUUGCAAUUAU AAUCUUACCAAAUUGCUUUCA

CUUUUUUCUGUGAAUGAUUUUACUUGUAGUCAAAUAUCUCCAGCAGCAAUUGCUAGC AACUGUUAUUCUUCACUGAUU

UUGGAUUACUUUUCAUACCCACUUAGUAUGAAAUCCGAUCUCAGUGUUAGUUCUGCU GGUCCAAUAUCCCAGUUUAAU

UAUAAACAGUCCUUUUCUAAUCCCACAUGUUUGAUUUUAGCGACUGUUCCUCAUAAC CUUACUACUAUUACUAAGCCU

CUUAAGUACAGCUAUAUUAACAAGUGCUCUCGUCUUCUUUCUGAUGAUCGUACUGAA GUACCUCAGUUAGUGAACGCU

AAUCAAUACUCACCCUGUGUAUCCAUUGUCCCAUCCACUGUGUGGGAAGACGGUGAU UAUUAUAGGAAACAACUAUCU

CCACUUGAAGGUGGUGGCUGGCUUGUUGCUAGUGGCUCAACUGUUGCCAUGACUGAG CAAUUACAGAUGGGCUUUGGU

AUUACAGUUCAAUAUGGUACAGACACCAAUAGUGUUUGCCCCAAGCUUGAAUUUGCU AAUGACACAAAAAUUGCCUCU

CAAUUAGGCAAUUGCGUGGAAUAUUCCCUCUAUGGUGUUUCGGGCCGUGGUGUUUUU CAGAAUUGCACAGCUGUAGGU

GUUCGACAGCAGCGCUUUGUUUAUGAUGCAUACCAGAAUUUAGUUGGCUAUUAUUCU GAUGAUGGCAACUACUACUGU

UUGCGUGCUUGUGUUAGUGUUCCUGUUUCUGUCAUCUAUGAUAAAGAAACUAAAACC CACGCUACUCUAUUUGGUAGU

GUUGCAUGUGAACACAUUUCUUCUACCAUGUCUCAAUACUCCCGUUCUACGCGAUCA AUGCUUAAACGGCGAGAUUCU

ACAUAUGGCCCCCUUCAGACACCUGUUGGUUGUGUCCUAGGACUUGUUAAUUCCUCU UUGUUCGUAGAGGACUGCAAG

UUGCCUCUCGGUCAAUCUCUCUGUGCUCUUCCUGACACACCUAGUACUCUCACACCU CGCAGUGUGCGCUCUGUUCCA

GGUGAAAUGCGCUUGGCAUCCAUUGCUUUUAAUCAUCCCAUUCAGGUUGAUCAACUU AAUAGUAGUUAUUUUAAAUUA

AGUAUACCCACUAAUUUUUCCUUUGGUGUGACUCAGGAGUACAUUCAGACAACCAUU CAGAAAGUUACUGUUGAUUGU

AAACAGUACGUUUGCAAUGGUUUCCAGAAGUGUGAGCAAUUACUGCGCGAGUAUGGC CAGUUUUGUUCCAAAAUAAAC

CAGGCUCUCCAUGGUGCCAAUUUACGCCAGGAUGAUUCUGUACGUAAUUUGUUUGCG AGCGUGAAAAGCUCUCAAUCA

UCUCCUAUCAUACCAGGUUUUGGAGGUGACUUUAAUUUGACACUUCUAGAACCUGUU UCUAUAUCUACUGGCAGUCGU

AGUGCACGUAGUGCUAUUGAGGAUUUGCUAUUUGACAAAGUCACUAUAGCUGAUCCU GGUUAUAUGCAAGGUUACGAU

GAUUGUAUGCAGCAAGGUCCAGCAUCAGCUCGUGAUCUUAUUUGUGCUCAAUAUGUG GCUGGUUAUAAAGUAUUACCU

CCUCUUAUGGAUGUUAAUAUGGAAGCCGCGUAUACUUCAUCUUUGCUUGGCAGCAUA GCAGGUGUUGGCUGGACUGCU

GGCUUAUCCUCCUUUGCUGCUAUUCCAUUUGCACAGAGUAUCUUUUAUAGGUUAAAC GGUGUUGGCAUUACUCAACAG

GUUCUUUCAGAGAACCAAAAGCUUAUUGCCAAUAAGUUUAAUCAGGCUCUGGGAGCU AUGCAAACAGGCUUCACUACA

ACUAAUGAAGCUUUUCGGAAGGUUCAGGAUGCUGUGAACAACAAUGCACAGGCUCUA UCCAAAUUAGCUAGCGAGCUA

UCUAAUACUUUUGGUGCUAUUUCCGCCUCUAUUGGAGACAUCAUACAACGUCUUGAU GUUCUCGAACAGGACGCCCAA

AUAGACAGACUUAUUAAUGGCCGUUUGACAACACUAAAUGCUUUUGUUGCACAGCAG CUUGUUCGUUCCGAAUCAGCU

GCUCUUUCCGCUCAAUUGGCUAAAGAUAAAGUCAAUGAGUGUGUCAAGGCACAAUCC AAGCGUUCUGGAUUUUGUGGU

CAAGGCACACAUAUAGUGUCCUUUGUUGUAAAUGCCCCUAAUGGCCUUUACUUCAUG CAUGUUGGUUAUUACCCUAGC

AACCACAUUGAGGUUGUUUCUGCUUAUGGUCUUUGCGAUGCAGCUAACCCUACUAAU UGUAUAGCCCCUGUUAAUGGC

UACUUUAUUAAAACUAAUAACACUAGGAUUGUUGAUGAGUGGUCAUAUACUGGCUCG UCCUUCUAUGCACCUGAGCCC

AUCACCUCCCUUAAUACUAAGUAUGUUGCACCACAUGUGACAUACCAAAACAUUUCU ACUAACCUCCCUCCUCCUCUU

CUCGGCAAUUCCACCGGGAUUGACUUCCAAGAUGAGUUGGAUGAGUUUUUCAAAAAU GUUAGCACCAGUAUACCUAAU

UUUGGUUCUCUAACACAGAUUAAUACUACAUUACUCGAUCUUACCUACGAGAUGUUG UCUCUUCAACAAGUUGUUAAA

GCCCUUAAUGAGUCUUACAUAGACCUUAAAGAGCUUGGCAAUUAUACUUAUUACAAC AAAUGGCCGUGGUACAUUUGG

CUUGGUUUCAUUGCUGGGCUUGUUGCCUUAGCUCUAUGCGUCUUCUUCAUACUGUGC UGCACUGGUUGUGGCACAAAC

UGUAUGGGAAAACUUAAGUGUAAUCGUUGUUGUGAUAGAUACGAGGAAUACGACCUC GAGCCGCAUAAGGUUCAUGUU

CACUAA

MERS-CoV Spike (S) Protein Amino Acid Sequence- SEQ ID NO: 19 Accession No. R9UQ53

MIHSVFLLMFLLTPTESYVDVGPDSVKSACIEVDIQQTFFDKTWPRP IDVSKADGI I YPQGRTYSNITITYQGLFPYQ GDHGDMYVYSAGHATGTTPQKLFVANYSQDVKQFANGFWRIGAAANSTGTVI I SPSTSATIRKI YPAFMLGSSVGNF SDGKMGRFFNHTLVLLPDGCGTLLRAFYCILEPRSGNHCPAGNSYTSFATYHTPATDCSD GNYNRNASLNSFKEYFNL RNCTFMYTYNITEDEILEWFGITQTAQGVHLFSSRYVDLYGGNMFQFATLPVYDTIKYYS I IPHS IRS IQSDRKAWAA FYVYKLQPLTFLLDFSVDGYIRRAIDCGFNDLSQLHCSYESFDVESGVYSVSSFEAKPSG SWEQAEGVECDFSPLLS GTPPQVYNFKRLVFTNCNYNLTKLLSLFSVNDFTCSQI SPAAIASNCYSSLILDYFSYPLSMKSDLSVSSAGP I SQFN YKQSFSNPTCLILATVPHNLTTITKPLKYSYINKCSRLLSDDRTEVPQLVNANQYSPCVS IVPSTVWEDGDYYRKQLS PLEGGGWLVASGSTVAMTEQLQMGFGITVQYGTDTNSVCPKLEFANDTKIASQLGNCVEY SLYGVSGRGVFQNCTAVG VRQQRFVYDAYQNLVGYYSDDGNYYCLRACVSVPVSVI YDKETKTHATLFGSVACEHI SSTMSQYSRSTRSMLKRRDS TYGPLQTPVGCVLGLVNSSLFVEDCKLPLGQSLCALPDTPSTLTPRSVRSVPGEMRLAS IAFNHP IQVDQLNSSYFKL S IPTNFSFGVTQEYIQTTIQKVTVDCKQYVCNGFQKCEQLLREYGQFCSKINQALHGANLR QDDSVRNLFASVKSSQS SP I IPGFGGDFNLTLLEPVS I STGSRSARSAIEDLLFDKVT IADPGYMQGYDDCMQQGPASARDLICAQYVAGYKVLP PLMDVNMEAAYTS SLLGS IAGVGWTAGLS SFAAIPFAQS IFYRLNGVGI TQQVLSENQKLIANKFNQALGAMQTGFTT TNEAFRKVQDAVNNNAQALSKLASELSNTFGAI SAS IGD I IQRLDVLEQDAQIDRLINGRLTTLNAFVAQQLVRSESA ALSAQLAKDKVNECVKAQSKRSGFCGQGTHIVSFWNAPNGLYFMHVGYYP SNHIEWSAYGLCDAANPTNC IAPVNG YF IKTNNTRIVDEWSYTGS SFYAPEP I TSLNTKYVAPHVTYQNI STNLPPPLLGNSTGIDFQDELDEFFKNVSTS IPN FGSLTQINTTLLDLTYEMLSLQQWKALNESYIDLKELGNYTYYNKWPWYIWLGF IAGLVALALCVFF ILCCTGCGTN CMGKLKCNRCCDRYEEYDLEPHKVHVH

M-CoV Spike (S) Protein RNA Coding Sequence - SEQ ID NO: 20 Accession No. S51114.1

UAAUCUAAACAUGCUGUUCGUCUUUAUUUUACUAUUACCCUCUUGUUUAGGGUAUAU UGGUGAUUUUAGAUGUAUCCA GACCGUGAAUUAUAACGGCAAUAAUGCUUCUGCGCCUAGCAUUAGCACCGAAGCAGUCGA UGUUUCCAAAGGUCUGGG CACUUACUAUGUUUUAGAUCGUGUUUACUUAAAUGCCACGUUAUUGCUUACUGGUUAUUA UCCUGUGGACGGUUCCAA UUAUCGGAAUCUCGCGCUUACAGGCACUAAUACCUUAAGCCUUACGUGGUUUAAACCACC CUUUCUAAGUGAGUUUAA UGAUGGUAUAUUUGCUAAGGUCCAGAACCUCAAGACAAAUACGCCAACAGGUGCAACCUC AUAUUUUCCCACUAUAGU UAUAGGUAGUUUGUUUGGUAACACUUCCUAUACCGUAGUUUUAGAGCCAUAUAAUAAUAU UAUAAUGGCUUCUGUUUG UACAUAUACCAUUUGUCAAUUACCUUACACACCCUGUAAGCCUAAUACCAAUGGUAAUCG UGUUAUUGGAUUUUGGCA CACAGAUGUCAAACCGCCGAUUUGUCUUUUAAAGCGUAAUUUUACGUUUAAUGUUAAUGC CCCUUGGCUUUAUUUCCA UUUUUAUCAGCAGGGUGGUACUUUUUAUGCGUACUAUGCGGAUAAACCUUCCGCUACUAC GUUUUUGUUUAGUGUGUA UAUUGGCGACAUUUUAACACAGUAUUUUGUGUUACCUUUUAUUUGUACUCCAACAGCUGG UAGCACUUUACUGCCGCU CUAUUGGGUUACACCUUUACUUAAGCGCCAAUAUUUGUUUAAUUUUAAUGAAAAGGGUGU CAUUACUAGUGCUGUUGA UUGCGCCAGCAGCUACAUUAGUGAAAUAAAAUGUAAGACCCAAAGUCUCUUACCGAGUAC UGGUGUCUAUGAUCUAUC CGGUUACACGGUCCAACCUGUUGGAGUUGUGUACCGGCGUGUUCCUAACCUACCUGAUUG UAAAAUAGAGGAAUGGCU CACUGCUAAAUCUGUGCCGUCACCUCUCAAUUGGGAGCGUAGGACUUUCCAAAAUUGUAA UUUUAAUUUAAGCAGCCU GCUACGUUAUGUCCAGGCUGAGUCUUUGUCGUGUAAUAAUAUUGAUGCGUCCAAAGUGUA UGGUAUGUGCUUUGGUAG UGUCUCAGUUGAUAAGUUUGCUAUCCCCCGAAGCCGUCAAAUUGAUUUACAAAUUGGCAA CUCCGGAUUUUUGCAAAC GGCUAAUUAUAAGAUUGAUACCGCUGCCACAUCAUGUCAGCUGUAUUACAGUCUUCCUAA GAAUAAUGUUACCAUAAA UAACUAUAACCCCUCGUCUUGGAAUAGGAGGUAUGGUUUUAAUGAUGCUGGUGUGUUUGG CAAAAGUAAACAUGAUGU UGCCUACGCCCAGCAAUGUUUUACUGUGCGACCUAGCUAUUGUCCGUGUGCACAACCGGA CAUAGUUAGCGCUUGCAC UAGUCAGACCAAACCCAUGUCUGCUUAUUGCCCCACAGGCACAAUUCAUCGUGAGUGUUC UCUUUGGAAUGGGCCCCA UUUGCGCUCGGCACGUGUAGGUUCCGGCACGUACACGUGUGAGUGCACUUGUAAACCCAA UCCAUUUGAUACGUAUGA UCUCCGCUGUGGGCAAAUUAAAACUAUUGUUAAUGUGGGCGAUCAUUGUGAAGGUCUGGG UGUUUUAGAAGAUAAAUG UGGCAAUAGCGAUCCACAUAAGGGCUGUUCUUGUGCCAAUGAUUCUUUUAUCGGAUGGUC ACAUGACACUUGUUUAGU AAAUGAUCGCUGCCAAAUUUUUGCUAACAUAUUGUUAAAUGGCAUUAAUAGUGGGACUAC GUGUUCCACAGAUUUACA AUUGCCUAAUACUGAAGUGGCCACUGGCGUUUGCGUCAGAUAUGACCUCUAUGGUAUUAC UGGUCAAGGUGUUUUUAA AGAGGUCAAGGCUGACUAUUAUAAUAGCUGGCAGGCCCUAUUAUAUGAUGUUAAUGGUAA CUUAAACGGGUUCCGUGA CCUUACCACUAACAAGACUUAUACGAUAAGGAGCUGUUAUAGUGGCCGUGUUUCUGCUGC AUAUCAUAAAGAAGCACC CGAACCGGCUCUGCUCUAUCGUAAUAUAAAUUGUAGUUAUGUUUUUACUAAUAAUAUUUC CCGUGAGGAAAACCCCCU UAACUAUUUUGAUAGUUAUUUGGGUUGUGUUGUUAAUGCUGAUAACCGCACGGAUGAGGC GCUUCCUAAUUGCGAUCU CCGUAUGGGUGCUGGACUAUGCGUAGAUUAUUCAAAGUCACGCAGAGCCCGCCGAUCAGU UUCUACUGGCUAUCGAUU AAC C AC AUUC GAGC C AU AC AU GC C GAU GUU AGU C AAU GAU AGC GUUC AAU C C GU AGGU GGAUU AU AU GAGAU GC AAAU ACCAACCAAUUUUACUAUUGGUCAUCAUGAGGAAUUCAUCCAGAUAAGGGCUCCCAAGGU GACUAUAGAUUGUGCUGC AUUUGUUUGUGGUGAUAACGCUGCAUGCAGACAGCAGUUGGUUGAGUAUGGCUCUUUUUG UGAUAAUGUUAAUGCCAU UCUUAAUGAGGUUAAUAACCUCUUGGAUAAUAUGCAAUUACAAGUUGCUAGUGCAUUAAU GCAGGGUGUUACUAUAAG UUCGAGGCUGCCAGAUGGCAUCUCCGGCCCUAUAGAUGACAUUAAUUUCAGUCCUCUACU UGGAUGCAUAGGUUCAAC AUGUGCUGAAGACGGCAAUGGACCUAGUGCGAUACGGGGGCGUUCAGCUAUAGAGGAUUU AUUAUUUGACAAGGUCAA ACUAUCUGACGUUGGCUUUGUCGAGGCUUAUAACAAUUGCACUGGUGGUCAAGAAGUUCG CGACCUCCUUUGCGUACA GUCUUUUAAUGGCAUCAAAGUAUUACCUCCCGUGUUGUCUGAGAGUCAAAUCUCUGGCUA CACAGCGGGUGCUACUGC GGCAGCUAUGUUCCCACCUUGGACUGCAGCUGCUGGUGUGCCAUUCAGUUUAAAUGUUCA AUAUAGGAUUAAUGGUUU AGGUGUCACUAUGAAUGUUCUUAGUGAGAACCAAAAGAUGAUUGCUAGUGCUUUUAACAA CGCGCUCGGUGCUAUUCA GGAAGGGUUCGAUGCAACCAAUUCUGCUCUAGGUAAGAUCCAGUCCGUUGUUAAUGCAAA CGCUGAAGCACUUAAUAA UUUAUUAAACCAACUUUCUAAUAGGUUUGGUGCUAUUAGUGCUUCUUUACAAGAAAUUCU AACGCGGCUUGACGCUGU AGAAGCAAAGGCCCAGAUAGAUCGUCUUAUUAAUGGCAGGUUAACUGCACUUAAUGCGUA UAUAUCCAAGCAACUCAG UGAUAGUACGCUUAUUAAAUUUAGUGCUGCUCAGGCCAUCGAAAAGGUCAAUGAGUGCGU UAAGAGCCAAACUACGCG CAUUAAUUUCUGUGGCAAUGGUAAUCACAUAUUAUCACUUGUCCAGAAUGCGCCUUAUGG CUUAUGUUUUAUUCAUUU CAGCUACGUGCCAACAUCCUUUAAAACGGCAAAUGUGAGUCCUGGACUAUGCAUUUCUGG UGAUAGAGGAUUGGCACC UAAAGCUGGAUAUUUUGUUCAAGAUAAUGGAGAGUGGAAGUUCACAGGCAGUAAUUAUUA CUACCCUGAACCCAUUAC

AGAUAAAAAUAGUGUUGUCAUGAUCAGUUGCGCUGUGAAUUACACAAAAGCGCCUGA AGUUUUCUUGAACAACUCAAU

ACCAAAUCUACCCGACUUUAAGGAGGAGUUAGAUAAAUGGUUUAAGAAUCAGACGUC UAUUGCGCCUGAUUUAUCCCU

CGAUUUCGAGAAGUUAAAUGUUACUUUCCUGGACCUGACUUAUGAGAUGAACAGGAU UCAGGAUGCAAUUAAGAAGUU

AAAUGAGAGCUACAUCAACCUCAAGGAAGUUGGCACAUAUGAAAUGUAUGUGAAAUG GCCUUGGUAUGUUUGGUUGCU

AAUUGGUUUAGCUGGUGUAGCCGUUUGUGUGUUAUUAUUCUUUAUAUGUUGCUGCAC AGGUUGCGGCUCAUGUUGUUU

UAGAAAAUGCGGAAGUUGUUGUGAUGAGUAUGGAGGACACCAGGACAGUAUUGUGAU ACAUAAUAUUUCAGCCCAUGA

GGAUUGACUAUCACA

M-CoV Spike (S) Protein Amino Acid Sequence- SEQ ID NO: 21 Accession No. P22432

MLFVFILLLPSCLGYIGDFRCIQTVNYNGNNASAPSISTEAVDVSKGLGTYYVLDRV YLNATLLLTGYYPVDGSNYRN LALTGTNTLSLTWFKPPFLSEFNDGIFAKVQNLKTNTPTGATSYFPTIVIGSLFGNTSYT WLEPYNNIIMASVCTYT ICQLPYTPCKPNTNGNRVIGFWHTDVKPPICLLKRNFTFNVNAPWLYFHFYQQGGTFYAY YADKPSATTFLFSVYIGD ILTQYFVLPFICTPTAGSTLLPLYWVTPLLKRQYLFNFNEKGVITSAVDCASSYISEIKC KTQSLLPSTGVYDLSGYT VQPVGWYRRVPNLPDCKIEEWLTAKSVPSPLNWERRTFQNCNFNLSSLLRYVQAESLSCN NIDASKVYGMCFGSVSV DKFAIPRSRQIDLQIGNSGFLQTANYKIDTAATSCQLYYSLPKNNVTINNYNPSSWNRRY GFNDAGVFGKSKHDVAYA QQCFTVRPSYCPCAQPDIVSACTSQTKPMSAYCPTGTIHRECSLWNGPHLRSARVGSGTY TCECTCKPNPFDTYDLRC GQIKTIVNVGDHCEGLGVLEDKCGNSDPHKGCSCANDSFIGWSHDTCLVNDRCQIFANIL LNGINSGTTCSTDLQLPN TEVATGVCVRYDLYGITGQGVFKEVKADYYNSWQALLYDVNGNLNGFRDLTTNKTYTIRS CYSGRVSAAYHKEAPEPA LLYRNINCSYVFTNNISREENPLNYFDSYLGCWNADNRTDEALPNCDLRMGAGLCVDYSK SRRARRSVSTGYRLTTF EPYMPMLVNDSVQSVGGLYEMQIPTNFTIGHHEEFIQIRAPKVTIDCAAFVCGDNAACRQ QLVEYGSFCDNVNAILNE VNNLLDNMQLQVASALMQGVTISSRLPDGISGPIDDINFSPLLGCIGSTCAEDGNGPSAI RGRSAIEDLLFDKVKLSD VGFVEAYNNCTGGQEVRDLLCVQSFNGIKVLPPVLSESQISGYTAGATAAAMFPPWTAAA GVPFSLNVQYRINGLGVT MNVLSENQKMIASAFNNALGAIQEGFDATNSALGKIQSWNANAEALNNLLNQLSNRFGAI SASLQEILTRLDAVEAK AQIDRLINGRLTALNAYISKQLSDSTLIKFSAAQAIEKVNECVKSQTTRINFCGNGNHIL SLVQNAPYGLCFIHFSYV PTSFKTANVSPGLCISGDRGLAPKAGYFVQDNGEWKFTGSNYYYPEPITDKNSWMISCAV NYTKAPEVFLNNSIPNL PDFKEELDKWFKNQTSIAPDLSLDFEKLNVTFLDLTYEMNRIQDAIKKLNESYINLKEVG TYEMYVKWPWYVWLLIGL AGVAVCVLLFFICCCTGCGSCCFRKCGSCCDEYGGHQDSIVIHNISAHED

HKUl-CoV Spike (S) Protein RNA Coding Sequence - SEQ ID NO: 22 Accession No. AY597011.2

AUGUUAUUAAUUAUUUUUAUUUUGCCUACAACAUUAGCUGUUAUAGGUGAUUUUAAU UGUACUAAUUUUGCUAUUAAU

GAUUUAAACACCACAGUUCCUCGCAUAAGUGAGUAUGUUGUGGAUGUUUCUUAUGGU UUGGGUACAUAUUAUAUACUU

GAUCGUGUUUAUUUAAAUACUACUAUAUUAUUUACUGGUUAUUUCCCUAAAUCUGGU GCCAAUUUUAGGGAUCUAUCU

UUAAAAGGUACUACAUAUUUGAGUACUCUUUGGUAUCAGAAACCCUUUUUAUCUGAU UUUAAUAAUGGUAUUUUUUCU

AGAGUUAAGAAUACUAAGUUGUAUGUUAAUAAAACUUUGUAUAGUGAGUUUAGUACU AUAGUUAUAGGUAGUGUUUUU

AUUAACAACUCUUAUACUAUUGUUGUUCAACCUCAUAAUGGUGUUUUGGAGAUUACA GCUUGUCAAUACACUAUGUGU

GAGUAUCCUCAUACUAUUUGUAAAUCUAAAGGUAGUUCUCGUAAUGAAUCUUGGCAU UUUGAUAAAUCUGAACCUUUG

UGUCUGUUCAAGAAAAAUUUUACUUAUAAUGUUUCUACAGAUUGGUUGUAUUUUCAU UUUUAUCAAGAACGUGGCACU

UUUUAUGCUUAUUAUGCUGAUUCUGGCAUGCCUACUACUUUUUUAUUUAGUUUGUAU CUUGGUACUCUUUUAUCUCAU

UAUUAUGUUUUGCCUUUGACUUGUAAUGCUAUAUCUUCUAAUACUGAUAAUGAGACU UUACAAUAUUGGGUCACACCU

UUGUCUAAACGCCAAUAUCUUCUUAAAUUUGACAACCGUGGUGUUAUUACUAAUGCU GUUGAUUGUUCUAGUAGUUUC

UUUAGCGAGAUUCAAUGUAAAACUAAAUCUUUAUUACCUAAUACUGGUGUUUAUGAC UUAUCUGGUUUUACUGUUAAG

CCUGUUGCAACUGUACAUCGUCGUAUUCCUGAUUUACCUGAUUGUGACAUUGAUAAA UGGCUUAACAAUUUUAAUGUA

CCCUCACCUCUUAAUUGGGAACGUAAAAUUUUUUCUAAUUGCAACUUUAAUUUGAGU ACUUUGCUUCGUUUAGUUCAU

ACUGAUUCUUUUUCUUGUAAUAAUUUUGAUGAAUCUAAGAUAUAUGGUAGUUGUUUU AAGAGUAUUGUUUUAGAUAAA

UUUGCCAUACCCAACUCCAGACGAUCUGAUUUGCAGUUGGGCAGUUCUGGUUUUCUG CAAUCUUCUAAUUAUAAAAUU

GACACUACUUCUAGUUCUUGUCAAUUGUAUUAUAGUUUGCCUGCAAUUAAUGUUACU AUUAAUAAUUAUAAUCCUUCU

UCUUGGAAUAGAAGGUAUGGUUUUAAUAAUUUUAAUUUGAGCUCUCAUAGUGUUGUU UACUCACGUUAUUGUUUUUCU

GUUAAUAAUACUUUUUGUCCUUGUGCUAAACCUUCUUUUGCUUCAAGUUGCAAGAGU CAUAAACCACCUUCUGCUUCC

UGUCCUAUUGGUACUAAUUAUCGUUCUUGUGAGAGUACUACUGUACUCGACCACACU GACUGGUGUAGGUGUUCUUGU

UUACCUGAUCCUAUAACUGCUUAUGACCCUAGGUCUUGUUCUCAAAAAAAGUCUCUG GUUGGUGUUGGUGAACAUUGU

GCAGGGUUCGGUGUUGAUGAAGAAAAGUGUGGUGUAUUGGAUGGAUCAUAUAAUGUU UCUUGUCUUUGUAGUACUGAU

GCCUUUCUAGGUUGGUCUUAUGACACUUGCGUCAGUAACAACCGUUGUAAUAUUUUU UCUAAUUUUAUUUUAAAUGGU

AUCAAUAGUGGUACCACUUGUUCUAAUGAUUUAUUGCAGCCUAAUACUGAAGUUUUU ACUGAUGUUUGUGUUGAUUAC

GACCUUUAUGGUAUUACAGGACAAGGUAUUUUUAAAGAAGUUUCUGCUGUUUAUUAU AAUAGUUGGCAAAAUCUUUUG UAUGAUUCUAAUGGCAACAUUAUUGGUUUUAAAGAUUUUGUUACUAAUAAAACAUAUAAU AUUUUCCCUUGUUAUGCA

GGAAGAGUUUCUGCUGCUUUUCAUCAAAAUGCUUCCUCUUUGGCUUUACUUUAUCGU AAUUUAAAAUGUAGCUAUGUU

UUGAAUAAUAUUUCUUUAACUACUCAGCCAUAUUUUGAUAGUUAUCUUGGUUGCGUU UUUAAUGCUGAUAAUUUAACU

GAUUAUUCUGUUUCUUCUUGUGCUCUUCGCAUGGGUAGUGGUUUUUGUGUUGAUUAU AACUCACCUUCUUCUUCCUCU

UCGCGUCGUAAACGUAGAAGUAUUUCUGCUUCUUAUCGUUUUGUUACUUUUGAACCC UUUAAUGUCAGUUUUGUUAAU

GACAGUAUUGAGUCUGUGGGUGGUCUUUAUGAGAUCAAAAUUCCCACUAACUUUACU AUAGUUGGUCAAGAGGAAUUU

AUUCAAACUAAUUCUCCUAAAGUUACUAUUGAUUGUUCUUUAUUUGUCUGUUCUAAU UAUGCAGCUUGCCAUGACUUA

UUGUCAGAGUAUGGCACUUUUUGUGAUAAUAUUAAUAGUAUUUUAGAUGAAGUUAAU GGUUUACUUGAUACUACUCAA

UUGCAUGUAGCUGAUACUCUUAUGCAAGGUGUCACACUUAGCUCCAAUCUUAAUACU AAUUUGCAUUUUGAUGUUGAU

AAUAUUAAUUUUAAAUCCCUAGUUGGAUGUUUAGGUCCACACUGCGGUUCUUCUUCU CGUUCUUUUUUUGAAGAUUUA

UUGUUUGACAAAGUUAAACUUUCAGAUGUUGGUUUUGUUGAAGCUUAUAACAAUUGU ACUGGUGGUAGUGAAAUUAGA

GAUCUUCUUUGUGUACAAUCCUUUAAUGGUAUUAAAGUUUUGCCUCCUAUUUUGUCU GAAUCUCAAAUUUCUGGUUAC

ACCACAGCCGCUACUGUUGCUGCUAUGUUUCCACCAUGGUCAGCAGCAGCUGGCAUA CCAUUUUCUCUUAAUGUACAA

UAUAGAAUUAAUGGUUUGGGUGUUACUAUGGAUGUUCUUAAUAAAAAUCAAAAGUUG AUAGCUACUGCUUUUAAUAAU

GCUCUUCUUUCUAUUCAGAAUGGUUUUAGUGCUACCAACUCUGCACUUGCUAAAAUA CAAAGUGUUGUUAAUUCUAAU

GCUCAAGCACUUAAUAGUUUGUUACAGCAAUUAUUUAAUAAAUUUGGUGCAAUUAGU UCUUCUUUACAAGAAAUUUUA

UCUCGUCUCGAUGCUUUAGAGGCUCAGGUUCAGAUUGAUAGGCUUAUUAAUGGUCGU UUAACUGCUUUAAAUGCUUAU

GUCUCUCAACAGCUUAGUGAUAUUUCUCUUGUAAAAUUUGGUGCUGCUUUAGCUAUG GAGAAGGUUAAUGAGUGUGUU

AAAAGUCAAUCUCCUCGUAUUAAUUUUUGUGGUAAUGGUAAUCAUAUUUUGUCAUUA GUUCAAAAUGCUCCUUAUGGU

UUGUUGUUUAUGCAUUUUAGUUAUAAACCUAUUUCUUUUAAAACUGUUUUAGUAAGU CCUGGUUUGUGUAUAUCAGGU

GAUGUAGGUAUUGCACCUAAACAAGGGUAUUUUAUUAAACAUAAUGAUCAUUGGAUG UUCACUGGUAGUUCUUACUAU

UAUCCUGAACCAAUUUCAGAUAAAAAUGUUGUUUUUAUGAAUACUUGUUCUGUUAAU UUUACUAAAGCGCCUCUUGUU

UAUUUGAAUCAUUCUGUACCAAAAUUGUCUGAUUUUGAAUCUGAGUUAUCUCAUUGG UUUAAAAAUCAAACAUCCAUU

GCGCCUAAUUUGACUUUAAAUCUUCAUACUAUUAAUGCUACUUUUUUAGAUUUGUAU UAUGAGAUGAAUCUUAUUCAA

GAGUCUAUUAAGUCUUUGAAUAAUAGUUAUAUCAAUCUUAAAGAUAUAGGUACAUAU GAAAUGUAUGUAAAAUGGCCU

UGGUAUGUUUGGCUACUAAUUUCUUUUUCAUUUAUAAUAUUCCUUGUAUUGCUCUUU UUUAUAUGUUGUUGUACUGGU

UGUGGUUCUGCAUGUUUUAGUAAAUGUCAUAAUUGUUGUGAUGAGUAUGGUGGUCAU CAUGAUUUUGUUAUCAAAACA

UCUCAUGAUGAUUAG

HKUl-CoV Spike (S) Protein Amino Acid Sequence- SEQ ID NO: 23 Accession No. Q5MQD0

MLLIIFILPTTLAVIGDFNCTNFAINDLNTTVPRISEYWDVSYGLGTYYILDRVYLN TTILFTGYFPKSGANFRDLS LKGTTYLSTLWYQKPFLSDFNNGIFSRVKNTKLYVNKTLYSEFSTIVIGSVFINNSYTIW QPHNGVLEITACQYTMC EYPHTICKSKGSSRNESWHFDKSEPLCLFKKNFTYNVSTDWLYFHFYQERGTFYAYYADS GMPTTFLFSLYLGTLLSH YYVLPLTCNAISSNTDNETLQYWVTPLSKRQYLLKFDNRGVITNAVDCSSSFFSEIQCKT KSLLPNTGVYDLSGFTVK PVATVHRRIPDLPDCDIDKWLNNFNVPSPLNWERKIFSNCNFNLSTLLRLVHTDSFSCNN FDESKIYGSCFKSIVLDK FAIPNSRRSDLQLGSSGFLQSSNYKIDTTSSSCQLYYSLPAINVTINNYNPSSWNRRYGF NNFNLSSHSWYSRYCFS VNNTFCPCAKPSFASSCKSHKPPSASCPIGTNYRSCESTTVLDHTDWCRCSCLPDPITAY DPRSCSQKKSLVGVGEHC AGFGVDEEKCGVLDGSYNVSCLCSTDAFLGWSYDTCVSNNRCNIFSNFILNGINSGTTCS NDLLQPNTEVFTDVCVDY DLYGITGQGIFKEVSAVYYNSWQNLLYDSNGNIIGFKDFVTNKTYNIFPCYAGRVSAAFH QNASSLALLYRNLKCSYV LNNISLTTQPYFDSYLGCVFNADNLTDYSVSSCALRMGSGFCVDYNSPSSSSSRRKRRSI SASYRFVTFEPFNVSFVN DSIESVGGLYEIKIPTNFTIVGQEEFIQTNSPKVTIDCSLFVCSNYAACHDLLSEYGTFC DNINSILDEVNGLLDTTQ LHVADTLMQGVTLSSNLNTNLHFDVDNINFKSLVGCLGPHCGSSSRSFFEDLLFDKVKLS DVGFVEAYNNCTGGSEIR DLLCVQSFNGIKVLPPILSESQISGYTTAATVAAMFPPWSAAAGIPFSLNVQYRINGLGV TMDVLNKNQKLIATAFNN ALLSIQNGFSATNSALAKIQSWNSNAQALNSLLQQLFNKFGAISSSLQEILSRLDALEAQ VQIDRLINGRLTALNAY VSQQLSDISLVKFGAALAMEKVNECVKSQSPRINFCGNGNHILSLVQNAPYGLLFMHFSY KPISFKTVLVSPGLCISG DVGIAPKQGYFIKHNDHWMFTGSSYYYPEPISDKNWFMNTCSVNFTKAPLVYLNHSVPKL SDFESELSHWFKNQTSI APNLTLNLHTINATFLDLYYEMNLIQESIKSLNNSYINLKDIGTYEMYVKWPWYVWLLIS FSFIIFLVLLFFICCCTG CGSACFSKCHNCCDEYGGHHDFVIKTSHDD

NL63-CoV Spike (S) Protein RNA Coding Sequence - SEQ ID NO: 24 Accession No. JQ771055.1

AUGAAACUUUUCUUGAUUUUGCUUGUUUUGCCCUUGGCCUCUUGCUUUUUCACAUGU AAUAGUAAUGCUAAUCUCUCU

AUGUUACAAUUAGGUGUUCCUGACAAUUCUUCAACUAUUGUCACGGGUUUAUUGCCA ACUCAUUGGAUUUGUGCUAAU

CAGAGUACAUCUGUUUACUCAGCCAAUGGUUUCUUUUAUAUUGAUGUUGGUAAUCAC CGUAGUGCUUUUGCACUCCAU

ACUGGUUAUUAUGAUGUUAAUCAGUAUUAUAUUUAUGUUACUAAUGAAAUAGGCUUA AAUGCUUCUGUUACUCUUAAG

AUUUGUAAGUUUGGUAUAAACACUACUUUUGAUUUUUUAAGUAAUUCUUCUAGUUCU UUUGACUGUAUAGUUAAUUUG UUAUUUACAGAACAGUUAGGUGCGCCUUUGGGCAUAACUAUAUCUGGUGAAACUGUGCGU CUGCAUUUAUAUAAUGUA

ACUCGUACUUUUUAUGUGCCAGCAGCUUAUAAACUUACUAAACUUAGUGUUAAAUGU UACUUUAACUAUUCCUGUGUU

UUUAGUGUUGUCAACGCCACCGUUACUGUGAAUGUCACCACACAUAAUGGCCGUGUA GUUAACUACACUGUUUGUGAU

GAUUGUAAUGGUUAUACUGAUAACAUAUUUUCUGUUCAACAGGAUGGCCGCAUUCCU AAUGGUUUCCCUUUUAAUAAU

UGGUUUUUGCUAACUAAUGGUUCCACACUAGUGGACGGGGUCUCUAGACUUUAUCAA CCACUCCGUUUAACUUGUUUA

UGGCCUGUACCUGGUCUUAAAUCUUCAACUGGUUUUGUUUAUUUUAAUGCCACUGGU UCUGAUGUUAAUUGUAACGGC

UAUCAACAUAAUUCUUUUGCUGAUGUUAUGCGUUACAAUCUUAACUUCAGUGCUAAU UCUGUGGAUAAUCUCAAGAGU

GGUGUUAUAGUUUUUAAAACUCUACAGUACGAUGUUCUGUUUUACUGUAGUAAUUCC UCUUCGGGCGUUCUAGAUACC

ACAAUACCUUUUGGCCCUUCCUCUCAACCUUAUUACUGUUUUAUAAAUAGUACCAUC AACACCACUCAUGUUAGCACU

UUUGUGGGUGUCCUACCACCCACUGUGCGUGAGAUUGUUGUUGCUAGAACUGGUCAG UUUUAUAUUAAUGGUUUUAAG

UAUUUUGAUUUGGGUUUUAUCGAAGCUGUCAAUUUUAAUGUCACAACUGCUAGUGCC ACAGAUUUUUGGACGGUUGCA

UUUGCUACUUUUGUUGAUGUUUUGGUUAAUGUUAGUGCAACUAAGAUUCAAAACUUA CUUUAUUGCGAUUCUCCAUUU

GAAAAGUUGCAGUGUGAGCACUUGCAGUUUGGAUUGCAAGAUGGUUUUUAUUCUGCA AAUUUUCUUGAUGAUAAUGUU

UUGCCUGAGACUUAUGUUGCACUCCCCAUUUAUUAUCAACACACGGACAUAAAUUUU ACUGCAACUGCAUCUUUUGGU

GGUUCUUGUUAUGUUUGUAAACCACACCAGGUUAAUAUAUCUCUUAAUGGUAACACU UCAGUGUGUGUUAGAACAUCU

CAUUUUUCAAUUAGGUAUAUUUAUAACCGCGUUAAGAGUGGUUCACCAGGUGACUCU UCAUGGCACAUUUAUUUAAAG

AGUGGCACUUGUCCAUUUUCUUUUUCUAAGUUAAAUAAUUUUCAAAAGUUUAAGACU AUUUGUUUCUCAACCGUCGCA

GUGCCUGGUAGUUGUAAUUUUCCACUUGAAGCCACCUGGCAUUACACUUCUUAUACU AUUGUUGGUGCUUUGUAUGUU

ACUUGGUCUGAAGGUAAUUCCAUUACUGGUGUACCUUAUCCUGUCUCUGGUAUUCGU GAGUUUAGUAAUUUAGUUUUA

AAUAAUUGUACCAAAUAUAAUAUUUAUGAUUAUGUUGGUACUGGAAUUAUACGUUCU UCAAACCAGUCACUUGCUGGU

GGUAUUACAUAUGUUUCUAACUCUGGUAAUUUACUUGGUUUUAAAAAUGUUUCCACU GGUAACAUUUUUAUUGUGACA

CCAUGUAACCAACCAGACCAAGUAGCUGUUUAUCAACAAAGCAUUAUUGGUGCCAUG ACUGCUGUUAAUGAGUCUAGA

UAUGGCUUGCAAAACUUACUACAGUUACCUAACUUUUAUUAUGUUAGUAAUGGUGGU AACAAUUGCACUACGGCCGUU

AUGACUUAUUCUAAUUUUGGUAUUUGUGCUGAUGGUUCUUUAAUUCCUGUUCGUCUG CGUAAUUCUAGUGAUAAUGGU

AUUUCAGCCAUAAUCACUGCUAAUUUAUCCAUUCCCUCUAACUGGACUACUUCAGUU CAAGUUGAGUACCUCCAAAUU

ACUAGUACUCCAAUAGUUGUUGAUUGUGCUACUUAUGUGUGUAAUGGUAACCCUCGC UGUAAGAAUCUACUUAAGCAG

UAUACUUCUGCUUGUAAAACUAUUGAAGAUGCCUUACGACUUAGUGCUCAUUUGGAA ACUAAUGAUGUUAGUAGUAUG

CUAACUUUCGAUAGCAAUGCUUUUAGUUUGGCUAAUGUUACUAGUUUUGGAGAUUAU AACCUUUCUAGUGUUUUACCU

CAGAGAAACAUUCAUUCAAGCCGUAUAGCAGGACGUAGUGCUUUGGAAGAUUUGUUG UUUAGCAAAGUUGUUACAUCU

GGUUUGGGUACUGUUGAUGUUGACUAUAAGUCUUGUACUAAAGGUCUUUCUAUUGCU GACCUUGCUUGUGCUCAGUAC

UACAAUGGCAUAAUGGUUUUGCCAGGUGUUGCUGAUGCUGAACGUAUGGCCAUGUAU ACAGGUUCUCUUAUAGGUGGC

AUGGUGCUCGGAGGUCUUACAUCAGCAGCCGCCAUACCUUUUUCUUUGGCACUGCAA GCACGACUUAAUUAUGUUGCU

UUACAAACUGAUGUGCUUCAAGAAAAUCAGAAAAUUUUGGCUGCAUCAUUUAAUAAG GCUAUUAAUAACAUUGUUGCU

UCUUUUAGUAGCGUUAAUGAUGCUAUUACACAAACUGCAGAGGCUAUACAUACUGUU ACUAUUGCACUUAAUAAGAUU

CAGGAUGUUGUUAAUCAACAGGGUAGUGCUCUUAACCAUCUCACUUCACAAUUGAGA CAUAAUUUUCAGGCCAUUUCU

AAUUCAAUUCAAGCUAUUUAUGACCGGCUUGAUUCAAUUCAAGCCGAUCAACAAGUU GACAGAUUAAUUACUGGACGG

CUUGCAGCUUUGAAUGCAUUUGUUUCCCAAGUUUUGAAUAAAUAUACUGAAGUUCGU AGUUCCAGACGCUUAGCACAG

CAGAAGAUUAAUGAAUGUGUCAAAUCACAAUCUAAUAGAUAUGGUUUUUGUGGCAAU GGCACCCAUAUCUUUUCAAUC

GUCAACUCAGCUCCAGAUGGUUUGCUUUUUCUUCAUACUGUUUUGCUGCCAACCGAC UACAAGAAUGUAAAGGCGUGG

UCGGGUAUCUGUGUUGAUGGCAUUUACGGCUAUGUUCUGCGUCAACCUAACUUGGUU CUUUAUUCUGAUAAUGGUGUU

UUUCGUGUAACUUCCAGGGUCAUGUUCCAACCUCGUUUACCUGUUUUGUCUGAUUUU GUGCAAAUAUAUAAUUGUAAU

GUUACUUUUGUUAACAUAUCUCGUGUCGAGUUACAUACUGUCAUACCUGACUACGUU GAUGUUAAUAAAACAUUACAA

GAGUUUGCACAAAACUUACCAAAGUAUGUUAAGCCUAAUUUUGACUUGACUCCUUUU AAUUUAACAUACCUUAAUUUG

AGUUCUGAGUUGAAGCAACUCGAAGCUAAAACUGCUAGUCUUUUCCAAACUACUGUU GAAUUACAAGGUCUUAUUGAU

CAGAUUAACAGUACAUAUGUUGAUUUGAAGUUGCUUAAUAGGUUUGAAAAUUAUAUU AAAUGGCCUUGGUGGGUUUGG

CUCAUUAUUUCUGUUGUUUUUGUUGUAUUGUUGAGUCUUCUUGUGUUUUGUUGUCUU UCUACAGGUUGUUGUGGUUGU

UGCAAUUGUUUAACUUCAUCAAUGCGAGGUUGUUGUGAUUGUGGUUCAACUAAACUU CCUUAUUACGAAUUUGAAAAG

GUCCACGUUCAAUAA

NL63-CoV Spike (S) Protein Amino Acid Sequence- SEQ ID NO: 25 Accession No. H9EJV2

MKLFLILLVLPLASCFFTCNSNANLSMLQLGVPDNSSTIVTGLLPTHWICANQSTSV YSANGFFYIDVGNHRSAFALH

TGYYDVNQYYIYVTNEIGLNASVTLKICKFGINTTFDFLSNSSSSFDCIVNLLFTEQ LGAPLGITI SGETVRLHLYNV

TRTFYVPAAYKLTKLSVKCYFNYSCVFSWNATVTVNVTTHNGRWNYTVCDDCNGYTD NIFSVQQDGRIPNGFPFNN

WFLLTNGSTLVDGVSRLYQPLRLTCLWPVPGLKSSTGFVYFNATGSDVNCNGYQHNS FADVMRYNLNFSANSVDNLKS

GVIVFKTLQYDVLFYCSNSSSGVLDTTIPFGPSSQPYYCFINSTINTTHVSTFVGVL PPTVREIWARTGQFYINGFK YFDLGFIEAVNFNVTTASATDFWTVAFATFVDVLVNVSATKIQNLLYCDSPFEKLQCEHL QFGLQDGFYSANFLDDNV LPETYVALPIYYQHTDINFTATASFGGSCYVCKPHQVNISLNGNTSVCVRTSHFSIRYIY NRVKSGSPGDSSWHIYLK SGTCPFSFSKLNNFQKFKTICFSTVAVPGSCNFPLEATWHYTSYTIVGALYVTWSEGNSI TGVPYPVSGIREFSNLVL NNCTKYNIYDYVGTGIIRSSNQSLAGGITYVSNSGNLLGFKNVSTGNIFIVTPCNQPDQV AVYQQSIIGAMTAVNESR YGLQNLLQLPNFYYVSNGGNNCTTAVMTYSNFGICADGSLIPVRLRNSSDNGISAIITAN LSIPSNWTTSVQVEYLQI TSTPIWDCATYVCNGNPRCKNLLKQYTSACKTIEDALRLSAHLETNDVSSMLTFDSNAFS LANVTSFGDYNLSSVLP QRNIHSSRIAGRSALEDLLFSKW TSGLGTVDVDYKSCTKGLSIADLACAQYYNGIMVLPGVADAERMAMYTGSLIGG MVLGGLTSAAAIPFSLALQARLNYVALQTDVLQENQKILAASFNKAINNIVASFSSVNDA ITQTAEAIHTVTIALNKI QDWNQQGSALNHLTSQLRHNFQAISNSIQAIYDRLDSIQADQQVDRLITGRLAALNAFVS QVLNKYTEVRSSRRLAQ QKINECVKSQSNRYGFCGNGTHIFSIVNSAPDGLLFLHTVLLPTDYKNVKAWSGICVDGI YGYVLRQPNLVLYSDNGV FRVTSRVMFQPRLPVLSDFVQIYNCNVTFVNISRVELHTVIPDYVDVNKTLQEFAQNLPK YVKPNFDLTPFNLTYLNL SSELKQLEAKTASLFQTTVELQGLIDQINSTYVDLKLLNRFENYIKWPWWVWLIISWFWL LSLLVFCCLSTGCCGC CNCLTSSMRGCCDCGSTKLPYYEFEKVHVQ

EQUIVALENTS

All references, patents and patent applications disclosed herein are incorporated by reference with respect to the subject matter for which each is cited, which in some cases may encompass the entirety of the document.

The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

The terms “about” and “substantially” preceding a numerical value mean ±10% of the recited numerical value.

Where a range of values is provided, each value between the upper and lower ends of the range are specifically contemplated and described herein.

The entire contents of International Application Nos. PCT/US2015/002740, PCT/US2016/043348, PCT/US2016/043332, PCT/US2016/058327, PCT/US2016/058324, PCT/US2016/058314, PCT/US2016/058310, PCT/US2016/058321, PCT/US2016/058297, PCT/US2016/058319, and PCT/US2016/058314 are incorporated herein by reference.