BISPECIFIC MOLECULES COMPRISING AN HIV-1 ENVELOPE TARGETING ARM

Title:

BISPECIFIC MOLECULES COMPRISING AN HIV-1 ENVELOPE TARGETING ARM

Document Type and Number:

WIPO Patent Application WO/2018/053328

Kind Code:

Abstract:

The invention is directed to multispecific molecules comprising an HIV-1 envelope targeting arm and an arm targeting an effector cell, compositions comprising these molecules and methods of use.

Inventors:

HAYNES BARTON F (US)
NORDSTROM JEFFREY LEE (US)
LAM CHIA-YING KAO (US)
MOODY M ANTHONY (US)
WILLIAMS LATONYA (US)

Application Number:

PCT/US2017/051877

Publication Date:

March 22, 2018

Filing Date:

September 15, 2017

Export Citation:

Click for automatic bibliography generation Help

Assignee:

UNIV DUKE (US)
MACROGENICS INC (US)

International Classes:

A61K38/00; A61K39/395; A61K39/42; C07K16/10; C07K16/46; C07K19/00

Domestic Patent References:

WO2016054101A1	2016-04-07
WO2015184207A1	2015-12-03
WO2013070776A1	2013-05-16

Foreign References:

US20150152167A1	2015-06-04
US20120269821A1	2012-10-25
US20160222105A1	2016-08-04

Attorney, Agent or Firm:

KIM, William W. et al. (US)

Download PDF:

View/Download PDF PDF Help

Claims:

CLAIMS

1. A bispecific molecule comprising a first polypeptide chain and a second polypeptide chain, covalently bonded to one another, wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VLl) having the binding specificity of a gp41 MPER binding HIV- 1 antibody (1);

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2); and

(iii) a domain (C) comprising a heterodimer promoting domain;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VHl) having the binding specificity of a gp41 MPER binding HIV- 1 antibody (1); and

(iii) a domain (F) comprising a heterodimer promoting domain; and wherein:

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site; and

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding HIV-1 antibody (1); and the domains (B) and (D) associate to form a binding site that binds the epitope (2).

2. The bispecific molecule of claim 1, wherein:

(i) domains (A) and (B) are separated by a peptide linker 1 ;

(ii) domains (C) and (B) are separated by a peptide linker 2;

(iii) domains (D) and (E) are separated by a peptide linker 1 ; and

(iv) domains (F) and (E) are separated by a peptide linker 2.

3. A bispecific molecule comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein the first and second polypeptide chains are covalently bonded and the second and third polypeptide chains are covalently bonded, and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VLl) having the binding specificity of a gp41 MPER binding HIV- 1 antibody (1);

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2);

(iii) a domain (C) comprising a heterodimer promoting domain; and

(iv) a CH2-CH3 domain;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VHl) having the binding specificity of a gp41 MPER binding HIV- 1 antibody (1); and

(iii) a domain (F) comprising a heterodimer promoting domain;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain, and wherein:

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding HIV-1 antibody (1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

4. The bispecific molecule of claim 3, wherein: (i) the third polypeptide chain further comprises a peptide linker 3 N-terminal to the CH2-CH3 domain;

(ii) domains (A) and (B) are separated by a peptide linker 1;

(iii) domains (C) and (B) are separated by a peptide linker 2;

(iv) the CH2-CH3 domain and domain (C) are separated by a peptide linker 3 or a spacer linker 3;

(v) domains (D) and (E) are separated by a peptide linker 1 ; and

(vi) domains (F) and (E) are separated by a peptide linker 2.

5. A bispecific molecule comprising a first polypeptide chain, a second polypeptide chain and a third polypeptide chain, wherein the first and second polypeptide chains are covalently bonded and the second and third polypeptide chains are covalently bonded, and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain;

(ii) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VLl) having the binding specificity of a gp41 MPER binding HIV- 1 antibody (1);

(iii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2); and

(iv) a domain (C) comprising a heterodimer promoting domain;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VHl) having the binding specificity of a gp41 MPER binding HIV- 1 antibody (1); and

(iii) a domain (F) comprising a heterodimer promoting domain;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain, and wherein:

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site; the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER bindingHIV-1 antibody (1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

6. The bispecific molecule of claim 5, wherein:

(i) the CH2-CH3 domain and domain (A) are separated by a peptide linker 4;

(ii) domains (A) and (B) are separated by a peptide linker 1 ;

(iii) domains (C) and (B) are separated by a peptide linker 2;

(iv) domains (D) and (E) are separated by a peptide linker 1 ;

(v) domains (F) and (E) are separated by a peptide linker 2;

(vi) the first polypeptide chain further comprises a peptide linker 3 N-terminal to the CH2-CH3 domain; and

(vii) the third polypeptide chain further comprises a peptide linker 3 N-terminal to the CH2-CH3 domain.

7. A bispecific molecule comprising a first polypeptide chain, a second polypeptide chain, a third polypeptide chain, and a fourth polypeptide chain, wherein the first and second polypeptide chains are covalently bonded and the first and third polypeptide chains are covalently bonded, and wherein:

(I) the first and the third polypeptide chains each comprise in the N- to C-terminal direction:

(i) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VLl) having the binding specificity of a gp41 MPER binding HIV- 1 antibody (1);

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2);

(iii) a domain (C) comprising a heterodimer promoting domain; and

(iv) a CH2-CH3 domain;

(II) the second and fourth polypeptide chains each comprise in the N- to C-terminal direction: (i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VH1) having the binding specificity of a gp41 MPER bindingHIV- 1 antibody (1);

(iii) a domain (F) comprising a heterodimer promoting domain; and wherein the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding HIV-1 antibody (1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

8. The bispecific molecule of claim 7, wherein:

(i) domains (A) and (B) are separated by a peptide linker 1 ;

(ii) domains (C) and (B) are separated by a peptide linker 2;

(iii) the CH2-CH3 domain and domain (C) are separated by a peptide linker 3 or a spacer linker 3;

(iv) domains (D) and (E) are separated by a peptide linker 1 ; and

(v) domains (F) and (E) are separated by a peptide linker 2.

9. A trivalent binding molecule comprising a first, second, third and fourth polypeptide chain wherein:

(I) the first polypeptide chain comprises in the N-terminus to C-terminus direction:

(i) a domain (A) comprising a binding region of a light chain variable domain of a first immunoglobulin (VL1) specific for an epitope (1);

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2);

(iii) a domain (C) comprising a heterodimer promoting domain; and

(iv) a CH2-CH3 Domain;

(II) the second polypeptide chain comprises, in the N-terminus to C-terminus direction: (i) a domain (D) comprising a binding region of a light chain variable domain of the first immunoglobulin (VL1) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the second immunoglobulin (VH1) specific for the epitope (1);

(iii) a domain (F) comprising a heterodimer promoting domain; and

(III) the third polypeptide chain that comprises, in the N-terminus to C-terminus direction:

(i) a domain (G) comprising a binding region of a heavy chain variable domain of a third immunoglobulin (VH3) specific for an epitope (3); and

(ii) a CHI -Hinge Domain, and a CH2-CH3 Domain; and

(IV) the fourth polypeptide chain that comprises, in the N-terminus to C-terminus direction:

(i) a domain (H) comprising a binding region of a light chain variable domain of the third immunoglobulin (VL3) specific for the epitope (3); and

(ii) CL Kappa Domain or a CL Lambda Domain; and wherein

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the domains (A) and (E) associate to form a binding site that binds the epitope (1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2);

the domains (G) and (H) associate to form a binding site that bind the epitope (3);

at least one of epitope (1), epitope (2), and epitope (3) is an epitope bound by an gp41 MPER binding HIV- 1 antibody, and at least one of epitope (1), epitope (2), and epitope (3) is an epitope of CD3, CD8, or CD 16;

the CH2-CH3 domains of the first and third polypeptide form an Fc Domain;

said first and second polypeptide chains are covalently bonded to one another;

said first and third polypeptide chains are covalently bonded to one another; and

said third and fourth polypeptide chains are covalently bonded to one another.

10. The trivalent binding molecule of claim 9, wherein:

(i) domains (A) and (B) are separated by a peptide linker 1 ;

(ii) domains (C) and (B) are separated by a peptide linker 2 or a peptide linker 2-C;

(iii) the CH2-CH3 domain and domain (C) are separated by a peptide linker 3 or a spacer linker 3; (iv) domains (D) and (E) are separated by a peptide linker 1 ; and

(v) domains (F) and (E) are separated by a peptide linker 2 or a peptide linker 2-C.

11. A trivalent binding molecule comprising a first, second, and third polypeptide chain wherein:

(I) the first polypeptide chain comprises in the N-terminus to C-terminus direction:

(i) a domain (A) comprising a binding region of a light chain variable domain of a first immunoglobulin (VL1) specific for an epitope (1);

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2);

(iii) a domain (C) comprising a heterodimer promoting domain; and

(iv) a CH2-CH3 Domain;

(II) the second polypeptide chain comprises, in the N-terminus to C-terminus direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the first immunoglobulin (VL1) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the second immunoglobulin (VH1) specific for the epitope (1);

(iii) a domain (F) comprising a heterodimer promoting domain; and

(III) the third polypeptide chain that comprises, in the N-terminus to C-terminus direction:

(i) a domain (H) comprising a binding region of a light chain variable domain of a third immunoglobulin (VL3) specific for an epitope (3)

(ii) a domain (G) comprising a binding region of a heavy chain variable domain of the third immunoglobulin (VH3) specific for the epitope (3);

(iii) a CH2-CH3 Domain; and wherein

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the domains (A) and (E) associate to form a binding site that binds the epitope (1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2);

the domains (G) and (H) associate to form a binding site that bind the epitope (3); at least one of epitope (1), epitope (2), and epitope (3) is an epitope bound by a gp41 MPER binding HIV-1 antibody, and at least one of epitope (1), epitope (2), and epitope (3) is and epitope of CD3, CD8, or CD 16;

the CH2-CH3 domains of the first and third polypeptide form an Fc Domain;

said first and second polypeptide chains are covalently bonded to one another;

said first and third polypeptide chains are covalently bonded to one another; and

said third and fourth polypeptide chains are covalently bonded to one another.

12. The trivalent binding molecule of claim 1 1, wherein:

(i) domains (A) and (B) are separated by a peptide linker 1 ;

(ii) domains (C) and (B) are separated by a peptide linker 2 or a peptide linker 2-C;

(iii) the CH2-CH3 domain and domain (C) are separated by a peptide linker 3 or a spacer linker 3;

(iv) domains (D) and (E) are separated by a peptide linker 1 ;

(v) domains (F) and (E) are separated by a peptide linker 2 or a peptide linker 2-C;

(vi) domains (H) and (G) are separated by a peptide linker 5; and

(vii) the CH2-CH3 domain and domain (G) are separated by a peptide linker 3.

13. The trivalent binding molecule of claims 9-12, wherein one of epitope ( 1), epitope (2), or epitope (3) is an epitope of CD8.

14. The molecules of claims 3-8 and 9-12, wherein the CH2-CH3 domain of the first

polypeptide chain is the of the "knob" design (SEQ ID NOs: 531 or 532) and the CH2- CH3 domain of the third polypeptide chain is of the "hole" design (SEQ ID NOs: 533 or 534).

15. The molecules of claim 14, wherein the CH2-CH3 domain of the first polypeptide

comprises SEQ ID NO: 531 and the CH2-CH3 domain of the third polypeptide chain comprises SEQ ID NO: 533.

16. The molecules of claims 3-8 and 9-12, wherein the CH2-CH3 domain of the third

polypeptide chain is the of the "knob" design (SEQ ID NOs: 531 or 532) and the CH2- CH3 domain of the first polypeptide chain is of the "hole" design (SEQ ID NOs: 533 or 534).

17. The molecules of claim 16, wherein the CH2-CH3 domain of the third polypeptide comprises SEQ ID NO: 531 and the CH2-CH3 domain of the first polypeptide chain comprises SEQ ID NO: 533.

18. The molecules of claims 1-12 wherein the epitope (2) is a CD3 epitope, CD8 epitope, or a CD 16 epitope.

19. The molecules of claims 1-12, wherein the gp41 MPER binding HIV-1 antibody is

DH51 1, DH51 1 2 K3, DH512, DH513, DH514, DH515, DH516, DH517, DH518, DH536, or DH537or any of the antibodies of the DH511 lineage.

20. The molecules of claims 1-12, wherein the molecule binds HIV-1 envelope with the specificity of the gp 41 MPER binding antibody DH512, DH511 2 K3 or any antibody of the DH51 1 lineage and binds CD3, CD8, or CD 16.

21. The molecules of claims 1-12, wherein domain (A) comprises the CDR1, CDR2, and CDR3 of the light chain variable domain of immunoglobulin DH512, DH51 1 2 K3 or any immunoglobulin of the DH51 1 lineage.

22. The molecules of claims 1-12, wherein domain (E) comprises the CDR1, CDR2, and CDR3 of the heavy chain variable domain of immunoglobulin DH512, or any immunoglobulin of the DH51 1 lineage.

23. The molecules of claims 1-12, wherein domain (A) comprises the light chain variable domain of immunoglobulin DH512, DH51 1 2 K3 or any immunoglobulin of the DH511 lineage.

24. The molecules of claims 1-12, wherein domain (E) comprises the heavy chain variable domain of immunoglobulin DH512, or any immunoglobulin of the DH51 1 lineage.

25. The molecules of claims 1-12, wherein domain (B) comprises the heavy chain variable domain of an anti-CD3 antibody.

26. The molecules of claims 1-12, wherein the domain (D) comprises the light chain variable domain of an anti-CD3 antibody.

27. The trivalent binding molecule of claims 9-12, wherein domain (G) comprises heavy chain variable domain of an anti-CD8 antibody.

28. The trivalent binding molecule of claims 9-12, wherein domain (H) comprises light chain variable domain of an anti-CD8 antibody.

29. The bispecific molecule of claim 3, wherein the first polypeptide comprises SEQ ID NO:

555, the second polypeptide comprises SEQ ID NO: 557, and the third polypeptide comprises SEQ ID NO: 559.

30. The trivalent binding molecule of claim 9, wherein a. the first polypeptide comprises SEQ ID NO: 555, the second polypeptide comprises SEQ ID NO: 557, the third polypeptide comprises SEQ ID NO: 561, and the fourth polypeptide comprises SEQ ID NO: 562; or

b. the first polypeptide comprises SEQ ID NO: 555, the second polypeptide comprises SEQ ID NO: 557, the third polypeptide comprises SEQ ID NO: 627, and the fourth polypeptide comprises SEQ ID NO: 628; or

c. comprises SEQ ID NO: 629, the second polypeptide comprises SEQ ID NO: 630, the third polypeptide comprises SEQ ID NO: 631, and the fourth polypeptide comprises SEQ ID NO: 632.

31. The trivalent binding molecule of claim 1 1, wherein the first polypeptide comprises SEQ ID NO: 555, the second polypeptide comprises SEQ ID NO: 557, and the third polypeptide comprises SEQ ID NO: 563.

32. A composition comprising any one of the molecules of claims 1-3 lor any combination thereof and a carrier.

33. A composition comprising a bispecific molecule or trivalent molecule which comprises at least one arm with the binding specificity of HIV- 1 antibody DH512, DH51 1 2 K3 or any antibody of the DH511 lineage, and a second arm targeting CD3, CD8 or CD 16.

34. The composition of claim 33, further comprising a second bispecific molecule or trivalent molecule comprising a first arm with the binding specificity of an HIV- 1 antibody different from the binding specificity of the first bispecific molecule or trivalent molecule and a second arm targeting CD3, CD8 or CD 16, wherein the first and second molecules are different.

35. A method to treat or prevent HIV- 1 infection in a subject in need thereof comprising

administering to the subject a composition comprising any one of the molecules of claim 1-31 or a combination of any one of these molecules in a therapeutically effective amount.

36. The method of claim 35, further comprising administering a latency activating agent.

37. The method of claim 36, wherein the latency activating agent is vorinostat, romidepsin, panobinostat, disulfiram, JQ 1, bryostatin, PMA, inonomycin, or any combination thereof.

38. A vector comprising nucleic acids comprising nucleotides encoding the molecules of any one of claim 1-31.

39. A composition comprising a vector comprising a nucleic acid encoding the molecules of any one of claim 1-31.

Description:

Bispecific Molecules Comprising an HIV-1 Envelope Targeting Arm

[0001] This invention claims the benefit of and priority to U.S. Serial No. 62/395,788, filed September 16, 2016, the contents of which is hereby incorporated by reference in its entirety.

[0002] This patent disclosure contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves any and all copyright rights.

[0003] All patents, patent applications and publications cited herein are hereby incorporated by reference in their entirety. The disclosure of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art as known to those skilled therein as of the date of the invention described herein.

FIELD OF THE INVENTION

[0004] The invention is directed to multispecific molecules, such as but not limited to bispecific and trispecific molecules (e.g. bispecific antibodies, bispecific diabodies, and trivalent binding molecules) comprising an HIV-1 binding domain and an effector cell binding domain, and their uses.

BACKGROUND

[0005] Highly Active Antiretroviral Therapy (HAART) has been effective in reducing the viral burden and ameliorating the effects of HIV-1 infection in infected individuals. However, despite this therapy the virus persists in the individual due to latent reservoir of HIV-1 infected cells which evade this treatment. Thus, there is a need for therapeutic agents for treatment of HIV-1 infected individuals, as well as agents that target virus infected cells and have the potential to reduce the latent reservoir of HIV-1 infected cells.

GOVERNMENT SUPPORT

[0006] This invention was made with government support under Grant No. UM1AI126619 awarded by National Institute of Allergy and Infectious Diseases. The Government has certain rights to the invention.

SUMMARY OF THE INVENTION

[0007] In some aspects the invention is directed to multispecific molecules, such as but not limited to bispecific and trispecific molecules (e.g. , bispecific antibodies, bispecific diabodies, trivalent binding molecules, etc.) which comprise epitope-binding fragments of antibodies (e.g. , VL and VH Domains) that enable them to coordinately bind immunospecifically to at least one target on HIV-1 envelope (e.g. but not limited to a membrane-proximal extracellar region of HIV-1 gp41 epitope) and at least one epitope of a second molecule that is not HIV-1 Env, for example but not limited to an effector cell which expresses CD2, CD3, CD8, CD 16, T-Cell Receptor (TCR), NKG2D, etc. epitope. In some embodiments, the MPER binding specificity of the molecules of the invention is different from the specificity of the MPER antibody 10E8.

[0008] Selection of the VL and VH Domains of the polypeptide domains of the multispecific molecules of the invention is coordinated so that the polypeptides chains that make up such multispecific molecules assemble to form at least one functional epitope-binding site that is specific for at least one epitope of HIV-1 Env and at least one functional epitope-binding site that is specific for at least one epitope of a molecule that is not HIV-1 Env. In some embodiments, the multispecific molecules of the invention comprise an Fc Domain (Fc bearing multispecific molecules of the invention).

[0009] In certain aspects, the invention provides multispecific molecules comprise an epitope- binding site that specifically binds the membrane-proximal extracellular region (MPER) of HIV-1 gp41. In non-limiting embodiments the multispecific molecules comprise the MPER binding portions from an antibody from Figure 13, Figure 55, Figure 56, Figure 57 or Figures 30-33 (antibodies with mutations in the DH512 or DH51 1 VH chain). In non-limiting embodiments, combination mutations in the DH512 or DH51 1 VHCDR3 could include VH LlOOdF together with TlOOaW Figures 31 and 32); VH LlOOdW together with TlOOaW (Figures 31 and 32). In some embodiments, the MPER binding portions of the multispecific molecule do not comprise portions for the antibody 10E8.

[0010] Non-limiting examples include multispecific molecules comprising VH or VL chains from DH511, DH512, DH512 K3, DH512-L100dF, DH513, DH514, DH515, DH516, DH517, DH518, DH536, DH537, lineage members, chimeric and mutant antibodies with non- limiting embodiments described in Examples 10, 1 1 or 12.

[0011] In non-limiting embodiments, the multispecific molecules comprise 1, 2 or all 3 of the CDRHS of a VH Domain with the specificity of the gp41 MPER binding antibody DH51 1 , DH512, DH512 K3, DH512-L100dF, DH513, DH514, DH515, DH516, DH517, DH518, DH 536, DH537, lineage members, chimeric and mutant antibodies with non-limiting

embodiments described in Example 1 1, and/or 1, 2 or all 3 of the CDRLS of a VL Domain of the gp41 MPER binding antibody DH511, DH512, DH512 K3, DH512-L100dF, DH513, DH514, DH515, DH516, DH517, DH518, DH536, DH537, lineage members, chimeric and mutant antibodies with non-limiting embodiments described in Examples 10, 1 1 or 12.

[0012] In non-limiting embodiments, the multispecific molecules comprise the VH Domain with the specificity of the gp41 MPER binding antibody DH51 1, DH512, DH512 K3, DH512-L100dF, DH513, DH514, DH515, DH516, DH517, DH518, DH536, DH537, lineage members, chimeric and mutant antibodies with non-limiting embodiments described in Example 1 1, and/or the VL Domain, of the gp41 MPER binding antibody DH51 1, DH512, DH512 K3, DH512-L100dF, DH513, DH514, DH515, DH516, DH517, DH518, DH536, DH537, lineage members, chimeric and mutant antibodies with non-limiting embodiments described in Examples 10, 1 1 or 12.

[0013] In certain embodiments an antibody (or a molecule comprising the CDRs, or the variable domains of such antibody) binds specifically to a particular target, peptide, or polysaccharide (such as an antigen present on the surface of a pathogen, for example gpl20, gp41, or CD3), even where the specific epitope may not be known, and do not bind in a significant amount to other proteins or polysaccharides present in the sample or subject. Specific binding can be determined by methods known in the art. Various competitive binding assays are known in the art. With reference to an antibody antigen complex, in certain embodiments specific binding of the antigen and antibody has a KD of less than about 10 ⁶ Molar, such as less than about 10 ⁶ Molar, 10 ⁷ Molar, 10 ⁸ Molar, 10 ⁹, or even less than about 10 ¹⁰ Molar.

[0014] In some aspects, the present invention is directed to bispecific molecules, e.g.

covalently linked polypeptide chains to form bispecific antibodies, covalently linked diabodies and/or trivalent binding molecules and their use in the treatment of HIV- 1. In certain aspects, the bispecific molecules of the present invention can bind to two different targets or epitopes on two different cells wherein the first epitope is expressed on a different cell type than the second epitope, such that the bispecific molecules can bring the two cells together. In certain aspects, the bispecific molecules of the present invention can bind to two different cells, wherein the bispecific molecules comprises an arm with the binding specificity for an HIV-1 envelope, for example as provided by the binding specificity of the gp41 MPER binding antibody DH511.2, a variant of DH51 1.2 called DH511 2 K3 and/or other antibodies from the DH51 1 lineage, and/or provided by any of the antibodies DH51 1, DH513, DH514, DH515, DH516, DH517, DH518, DH536, or DH537, which arm binds to the HIV-1 envelope expressed on a first cell, e.g. HIV-1 infected cell, and a second arm with the binding specificity for an epitope expressed on a different cell type than the first cell, such that the bispecific molecules can bring the two cells together. In certain embodiment, the second cell is in effector cell which expresses CD2, CD3, CD8, CD 16, T-Cell Receptor (TCR), NKG2D, etc. epitope.

[0015] In certain aspects, the invention provides a bispecific molecule comprising a first polypeptide chain and a second polypeptide chain, covalently bonded to one another, wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VL1) having the binding specificity of a gp41 MPER binding HIV-1 antibody (1);

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2); and

(iii) a domain (C) comprising a heterodimer promoting domain;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VH1) having the binding specificity of a gp41 MPER binding HIV- 1 antibody (1); and

(iii) a domain (F) comprising a heterodimer promoting domain; and wherein:

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site; and

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding HIV-1 antibody (1); and

the domains (B) and (D) associate to form a binding site that binds the epitope (2).

[0016] In certain aspects the invention provides such bispecific molecules wherein:

(i) domains (A) and (B) are separated by a peptide linker 1 ;

(ii) domains (C) and (B) are separated by a peptide linker 2; (iii) domains (D) and (E) are separated by a peptide linker 1 ; and

(iv) domains (F) and (E) are separated by a peptide linker 2.

[0017] In certain aspects the invention provides bispecific molecules comprising a first polypeptide chain and a second polypeptide chain, covalently bonded to one another, wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VL1) having the binding specificity of the gp41 MPER binding antibody DH511.2, a variant of DH511.2 called DH511 2 K3, or any antibody of the DH511 lineage (1);

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2), wherein domains (A) and (B) are separated from one another by a peptide linker 1 ; and

(iii) a domain (C) comprising a heterodimer promoting domain, including but not limited to a K coil or E coil; wherein domain (C) and domain (B) are separated by a peptide linker

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VH1) having the binding specificity of the gp41 MPER binding antibody DH511.2, a variant of DH511.2 called DH511 2 K3, or any antibody of the DH511 lineage (1), wherein domains (D) and (E) are separated from one another by a peptide linker 1 ; and

(iii) a domain (F) comprising a heterodimer promoting domain, including but not limited to a K coil or E coil; wherein domain (F) and domain (E) are separated by a peptide linker 2; and wherein:

the domains (A) and (B) do not associate with one another to form an epitope binding site; the domains (D) and (E) do not associate with one another to form an epitope binding site; and

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like the gp41 MPER binding antibody DH511.2, a variant of DH511.2 called DH511 2 K3, or any antibody of the DH51 1 lineage (1); and the domains (B) and (D) associate to form a binding site that binds the epitope (2).

[0018] In certain aspects the invention provides such bispecific molecules, wherein the first or second polypeptide chain further comprises an Fc Domain. The invention also provides such bispecific molecules wherein the first or second polypeptide chain further comprises an Fc Domain and the bispecific molecule further comprises a third polypeptide chain.

[0019] In certain aspects, the invention provides bispecific molecules comprising a first polypeptide chain and a second polypeptide chain, covalently bonded to one another, wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (A) comprising SEQ ID NO: 553, 570, 574, 578, 582, 586, 590, 594, 598, 602, 606, or 625;

(ii) a domain (B) comprising SEQ ID NO: 500 or 504; and

(iii) a domain (C) comprising SEQ ID NO: 520, 521, 518, or 519;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising SEQ ID NO: 502, or 506;

(ii) a domain (E) comprising SEQ ID NO: 551, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608-624, or 626 (Table 4); and

(iii) a domain (F) comprising SEQ ID NO: 518, 519, 520, or 521 ; and wherein:

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site; and

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding antibody ( 1); and

the domains (B) and (D) associate to form a binding site that binds an epitope (2).

[0020] In certain aspects the invention provides such bispecific molecules wherein:

(i) domains (A) and (B) are separated by SEQ ID NO: 508;

(ii) domains (C) and (B) are separated by SEQ ID NO: 509 or 510;

(iii) domains (D) and (E) are separated by SEQ ID NO: 508; and

(iv) domains (F) and (E) are separated by SEQ ID NO: 509 or 510. [0021] In certain aspects the invention provides bispecific molecules comprising a first polypeptide chain and a second polypeptide chain, covalently bonded to one another, wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (A) comprising SEQ ID NO: 553, 570, 574, 578, 582, 586, 590, 594, 598, 602, 606, or 625;

(ii) a domain (B) comprising SEQ ID NO:500 or 504, wherein domains (A) and (B) are separated from one another by SEQ ID NO: 508; and

(iii) a domain (C) comprising SEQ ID NO: 520, 521, 518, or 519; wherein domain (C) and domain (B) are separated by SEQ ID NO: 509 or 510;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising SEQ ID NO: 502, or 506;

(ii) a domain (E) comprising SEQ ID NO: 551, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604 608-624, or 626 (Table 4), wherein domains (D) and (E) are separated from one another by SEQ ID NO: 508; and

(iii) a domain (F) comprising SEQ ID NO: 518, 519, 520, or 521; wherein domain (F) and domain (E) are separated by SEQ ID NO: 509 or 510; and wherein:

the domains (A) and (B) do not associate with one another to form an epitope binding site; the domains (D) and (E) do not associate with one another to form an epitope binding site; and

wherein if the domain (A) comprises SEQ ID NO: 553 and domain (E) comprises SEQ ID NO: 551 they associate to form a binding site that binds the HIV-1 envelope like antibody DH511.2 K3;

wherein if the domain (A) comprises SEQ ID NO: 570 and domain (E) comprises SEQ ID NO: 568 they associate to form a binding site that binds the HIV-1 envelope like antibody DH511;

wherein if the domain (A) comprises SEQ ID NO: 574 and domain (E) comprises SEQ ID NO: 572 they associate to form a binding site that binds the HIV-1 envelope like antibody DH512 (also referred to as DH511.2);

wherein if the domain (A) comprises SEQ ID NO: 578 and domain (E) comprises SEQ ID NO: 576 they associate to form a binding site that binds the HIV-1 envelope like antibody DH513; wherein if the domain (A) comprises SEQ ID NO: 582 and domain (E) comprises SEQ ID NO: 580 they associate to form a binding site that binds the HIV-1 envelope like antibody DH514;

wherein if the domain (A) comprises SEQ ID NO: 586 and domain (E) comprises SEQ ID NO: 584 they associate to form a binding site that binds the HIV-1 envelope like antibody DH515;

wherein if the domain (A) comprises SEQ ID NO: 590 and domain (E) comprises SEQ ID NO: 588 they associate to form a binding site that binds the HIV-1 envelope like antibody DH516;

wherein if the domain (A) comprises SEQ ID NO: 594 and domain (E) comprises SEQ ID NO: 592 they associate to form a binding site that binds the HIV-1 envelope like antibody DH517;

wherein if the domain (A) comprises SEQ ID NO: 598 and domain (E) comprises SEQ ID NO: 596 they associate to form a binding site that binds the HIV-1 envelope like antibody DH518;

wherein if the domain (A) comprises SEQ ID NO: 602 and domain (E) comprises SEQ ID NO: 600 they associate to form a binding site that binds the HIV-1 envelope like antibody DH536; or

wherein if the domain (A) comprises SEQ ID NO: 606 and domain (E) comprises SEQ ID NO: 604 they associate to form a binding site that binds the HIV-1 envelope like antibody DH537; or

wherein if the domain (A) comprises SEQ ID NO: 625 and domain (E) comprises SEQ ID NO: 624 or 626 they associate to form a binding site that binds the HIV-1 envelope like antibody DH51 l_5a or DH51 l_5b; and

wherein if the domain (B) comprises SEQ ID NO: 500 and domain (D) comprises SEQ ID NO: 502 they associate to form a binding site that binds CD3; or

wherein if the domain (B) comprises SEQ ID NO: 504 and domain (D) comprises SEQ ID NO: 506 they associate to form a binding site that binds CD 16.

[0022] In certain aspects the invention provides a bispecific molecule comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein some of the polypeptides are covalently bonded (See Figure 103), and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction: (i) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VL1) having the binding specificity of a gp41 MPER binding antibody

(i) ;

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2);

(iii) a domain (C) comprising a heterodimer promoting domain; and

(iv) a CH2-CH3 domain;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VH1) having the binding specificity of a gp41 MPER binding antibody (l); and

(iii) a domain (F) comprising a heterodimer promoting domain;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain, and wherein:

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding antibody (1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0023] In certain aspects the invention provides such bispecific molecules wherein:

(i) the third polypeptide chain further comprises a peptide linker 3 N-terminal to the CH2-CH3 domain;

(ii) domains (A) and (B) are separated by a peptide linker 1;

(iii) domains (C) and (B) are separated by a peptide linker 2;

(iv) the CH2-CH3 domain and domain (C) are separated by a peptide linker 3 or a spacer linker 3;

(v) domains (D) and (E) are separated by a peptide linker 1 ; and (vi) domains (F) and (E) are separated by a peptide linker 2.

[0024] In certain aspects the invention provides bispecific molecules comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein some of the polypeptides are covalently bonded (See Figure 103), and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(iii) a domain (C) comprising a heterodimer promoting domain, including but not limited to a K coil or E coil; wherein domain (C) and domain (B) are separated by a peptide linker

(iv) a CH2-CH3 domain, wherein the CH2-CH3 domain and domain (C) are separated by a peptide linker 3 or a spacer-linker 3;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(iii) a domain (F) comprising a heterodimer promoting domain, including but not limited to a K coil or E coil; wherein domain (F) and domain (E) are separated by a peptide linker

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) a peptide linker 3,

(ii) a CH2-CH3 domain, and wherein: the domains (A) and (B) do not associate with one another to form an epitope binding site; the domains (D) and (E) do not associate with one another to form an epitope binding site; the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like the gp41 MPER binding antibody DH51 1.2, a variant of DH51 1.2 called DH51 1 2 K3, or any antibody of the DH51 1 lineage ( 1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0025] In certain aspects said first and second polypeptide chains are covalently bonded to one another; and said first and third polypeptide chains are covalently bonded to one another.

[0026] In certain aspects the invention provides a bispecific molecule comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein the first and second polypeptide chains are covalently bonded and the first and third polypeptide chains are covalently bonded, and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (A) comprising SEQ ID NO: 553, 570, 574, 578, 582, 586, 590, 594, 598, 602, 606, or 625;

(ii) a domain (B) comprising SEQ ID NO:500 or 504;

(iii) a domain (C) comprising SEQ ID NO: 520, 521, 518, or 519; and

(iv) a CH2-CH3 domain comprising SEQ ID NO: 531, 532, 533, or 534;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising SEQ ID NO: 502, or 506;

(ii) a domain (E) comprising SEQ ID NO: 551, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608-624, or 626 (Table 4); and

(iii) a domain (F) comprising SEQ ID NO: 518, 519, 520, or 521;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain comprising SEQ ID NO: 531, 532, 533, or 534; and wherein: the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site; the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding antibody (1);

the domains (B) and (D) associate to form a binding site that binds an epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0027] In certain aspects the invention provides such bispecific molecules wherein:

(i) the third polypeptide chain further comprises SEQ ID NO: 523 N-terminal to the CH2-CH3 domain;

(ii) domains (A) and (B) are separated by SEQ ID NO: 508;

(iii) domains (C) and (B) are separated by SEQ ID NO: 509 or 510;

(iv) the CH2-CH3 domain and domain (C) are separated by SEQ ID NO: 523 or 522;

(v) domains (D) and (E) are separated by SEQ ID NO: 508; and

(vi) domains (F) and (E) are separated by SEQ ID NO: 509 or 510.

[0028] In certain aspects the invention provides bispecific molecules comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein the first and second polypeptide chains are covalently bonded and the first and third polypeptide chains are covalently bonded, and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (A) comprising SEQ ID NO: 553, 570, 574, 578, 582, 586, 590, 594, 598, 602, 606, or 625;

(ii) a domain (B) comprising SEQ ID NO:500 or 504, wherein domains (A) and (B) are separated SEQ ID NO: 508;

(iii) a domain (C) comprising SEQ ID NO: 513, 520, 51 1, or 518; wherein domain (C) and domain (B) are separated by SEQ ID NO: 509 or 510;

(iv) a CH2-CH3 domain comprising SEQ ID NO: 531, 532, 533, or 534, wherein the CH2-CH3 domain and domain (C) are separated by SEQ ID NO: 523 or 522;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising SEQ ID NO: 502, or 506;

(ii) a domain (E) comprising SEQ ID NO: 551, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608-624, or 626 (Table 4), wherein domains (D) and (E) are separated from one another by SEQ ID NO: 508; and (iii) a domain (F) comprising SEQ ID NO: 513, 520, 511, or 518; wherein domain (F) and domain (E) are separated by SEQ ID NO: 509 or 510;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) SEQ ID NO: 523; and

(ii) a CH2-CH3 domain comprising SEQ ID NO: 531, 532, 533, or 534; and wherein: the domains (A) and (B) do not associate with one another to form an epitope binding site; the domains (D) and (E) do not associate with one another to form an epitope binding site; and

wherein if the domain (A) comprises SEQ ID NO: 553 and domain (E) comprises SEQ ID NO: 551 they associate to form a binding site that binds the HIV-1 envelope like antibody DH511.2 K3;

wherein if the domain (A) comprises SEQ ID NO: 570 and domain (E) comprises SEQ ID NO: 568 they associate to form a binding site that binds the HIV-1 envelope like antibody DH511;

wherein if the domain (A) comprises SEQ ID NO: 578 and domain (E) comprises SEQ ID NO: 576 they associate to form a binding site that binds the HIV-1 envelope like antibody DH513;

wherein if the domain (A) comprises SEQ ID NO: 582 and domain (E) comprises SEQ ID NO: 580 they associate to form a binding site that binds the HIV-1 envelope like antibody DH514;

wherein if the domain (A) comprises SEQ ID NO: 586 and domain (E) comprises SEQ ID NO: 584 they associate to form a binding site that binds the HIV-1 envelope like antibody DH515;

wherein if the domain (A) comprises SEQ ID NO: 590 and domain (E) comprises SEQ ID NO: 588 they associate to form a binding site that binds the HIV-1 envelope like antibody DH516;

wherein if the domain (A) comprises SEQ ID NO: 594 and domain (E) comprises SEQ ID NO: 592 they associate to form a binding site that binds the HIV-1 envelope like antibody DH517; wherein if the domain (A) comprises SEQ ID NO: 598 and domain (E) comprises SEQ ID NO: 596 they associate to form a binding site that binds the HIV-1 envelope like antibody DH518;

wherein if the domain (A) comprises SEQ ID NO: 602 and domain (E) comprises SEQ ID NO: 600 they associate to form a binding site that binds the HIV-1 envelope like antibody DH536;

wherein if the domain (A) comprises SEQ ID NO: 606 and domain (E) comprises SEQ ID NO: 604 they associate to form a binding site that binds the HIV-1 envelope like antibody DH537; or

wherein if the domain (B) comprises SEQ ID NO: 500 and domain (D) comprises SEQ ID NO: 502 they associate to form a binding site that binds CD3; or

wherein if the domain (B) comprises SEQ ID NO: 504 and domain (D) comprises SEQ ID NO: 506 they associate to form a binding site that binds CD16; and

the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0029] In certain aspects the invention provides bispecific molecules comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein some of the polypeptides are covalently bonded (See Figure 103), and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain;

(ii) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VL1) having the binding specificity of a gp41 MPERbinding antibody (1);

(iii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2); and

(iv) a domain (C) comprising a heterodimer promoting domain;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(iii) a domain (F) comprising a heterodimer promoting domain;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain, and wherein:

the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding antibody (1); the domains (B) and (D) associate to form a binding site that binds the epitope (2); and

the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0030] In certain aspects the invention provides such bispecific molecules wherein:

(i) the CH2-CH3 domain and domain (A) are separated by a peptide linker 4;

(ii) domains (A) and (B) are separated by a peptide linker 1;

(iii) domains (C) and (B) are separated by a peptide linker 2;

(iv) domains (D) and (E) are separated by a peptide linker 1 ;

(v) domains (F) and (E) are separated by a peptide linker 2;

(vi) the first polypeptide chain further comprises a peptide linker 3 N-terminal to the CH2- CH3 domain; and

(vii) the third polypeptide chain further comprises a peptide linker 3 N-terminal to the CH2-CH3 domain.

[0031] In other aspects the invention provides bispecific molecules comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein some of the polypeptides are covalently bonded (See Figure 103), and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a peptide linker 3 followed by a CH2-CH3 domain;

(ii) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VL1) having the binding specificity of the gp41 MPER binding antibody DH511.2, a variant of DH511.2 called DH511 2 K3, or any antibody of the DH511 lineage (1), wherein the CH2-CH3 domain and domain (A) are separated by a peptide linker 4;

(iii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2), wherein domains (A) and (B) are separated by a peptide linker 1 ;

(iv) a domain (C) comprising a heterodimer promoting domain, including but not limited to a K coil or E coil; wherein domain (C) and domain (B) are separated by a peptide linker 2;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(iii) a domain (F) comprising a heterodimer promoting domain, including but not limited to a K coil or E coil; wherein domain (F) and domain (E) are separated by a peptide linker 2;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) a peptide linker 3,

(ii) a CH2-CH3 domain, and wherein:

the domains (A) and (B) do not associate with one another to form an epitope binding site; the domains (D) and (E) do not associate with one another to form an epitope binding site; the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like the gp41 MPER binding antibody DH511.2, a variant of DH511.2 called DH511 2 K3, or any antibody of the DH511 lineage (1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain. [0032] In certain aspects said first and second polypeptide chains are covalently bonded to one another; and said first and third polypeptide chains are covalently bonded to one another.

[0033] In certain aspects the invention provides bispecific molecules comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein the first and second polypeptide chains are covalently bonded and the first and third polypeptide chains are covalently bonded (See Figure 103), and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain comprising SEQ ID NO: 531, 532, 533, or 534;

(ii) a domain (A) comprising SEQ ID NO: 553, 570, 574, 578, 582, 586, 590, 594, 598, 602, 606, or 625;

(iii) a domain (B) comprising SEQ ID NO:500 or 504; and

(iv) a domain (C) comprising SEQ ID NO: 520, 521, 518, or 519;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising SEQ ID NO: 502, or 506;

(ii) a domain (E) comprising SEQ ID NO: 551, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608-624, or 626 (Table 4); and

(iii) a domain (F) comprising SEQ ID NO: 518, 519, 520, or 521 ;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) a CH2-CH3 domain comprising SEQ ID NO: 531, 532, 533, or 534, and wherein: the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0034] In certain aspects the invention provides such bispecific molecules wherein:

(i) the CH2-CH3 domain and domain (A) are separated by SEQ ID NO: 524 or 525;

(ii) domains (A) and (B) are separated by SEQ ID NO: 508;

(iii) domains (C) and (B) are separated by SEQ ID NO: 509 or 510; (iv) domains (D) and (E) are separated by SEQ ID NO: 508;

(v) domains (F) and (E) are separated by SEQ ID NO: 509 or 510;

(vi) the first polypeptide chain further comprises SEQ ID NO: 523 N-terminal to the CH2- CH3 domain; and

(vii) the third polypeptide chain further comprises SEQ ID NO: 523 N-terminal to the CH2-CH3 domain.

[0035] In other aspects the invention provides bispecific molecules comprising a first polypeptide chain, a second polypeptide chain, and a third polypeptide chain, wherein the first and second polypeptide chains are covalently bonded and the first and third polypeptide chains are covalently bonded (See Figure 103), and wherein:

(I) the first polypeptide chain comprises in the N- to C-terminal direction:

(i) SEQ ID NO: 523 followed by a CH2-CH3 domain comprising SEQ ID NO: 531, 532, 533, or 534;

(ii) a domain (A) comprising SEQ ID NO: 553, 570, 574, 578, 582, 586, 590, 594, 598, 602, 606, or 625, wherein the CH2-CH3 domain and domain (A) are separated SEQ ID NO: 524 or 525;

(iii) a domain (B) comprising SEQ ID NO: 500 or 504, wherein domains (A) and (B) are separated by SEQ ID NO: 508;

(iv) a domain (C) comprising SEQ ID NO: 520, 521, 518, or 519; wherein domain (C) and domain (B) are separated by SEQ ID NO: 509 or 510;

(II) the second polypeptide chain comprises in the N- to C-terminal direction:

(i) a domain (D) comprising SEQ ID NO: 502, or 506;

(ii) a domain (E) comprising SEQ ID NO: 551, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608-624, or 626 (Table 4), wherein domains (D) and (E) are separated by SEQ ID NO: 508; and

(iii) a domain (F) comprising SEQ ID NO: 518, 519, 520, or 521; wherein domain (F) and domain (E) are separated by SEQ ID NO: 509 or 510;

(III) the third polypeptide chain comprises in the N- to C-terminal direction:

(i) SEQ ID NO: 523,

(ii) a CH2-CH3 domain comprising SEQ ID NO: 531, 532, 533, or 534, and wherein: the domains (A) and (B) do not associate with one another to form an epitope binding site; the domains (D) and (E) do not associate with one another to form an epitope binding site; wherein if the domain (A) comprises SEQ ID NO: 553 and domain (E) comprises SEQ ID NO: 551 they associate to form a binding site that binds the HIV-1 envelope like antibody DH511.2 K3;

wherein if the domain (A) comprises SEQ ID NO: 570 and domain (E) comprises SEQ ID NO: 568 they associate to form a binding site that binds the HIV-1 envelope like antibody DH511;

wherein if the domain (A) comprises SEQ ID NO: 578 and domain (E) comprises SEQ ID NO: 576 they associate to form a binding site that binds the HIV-1 envelope like antibody DH513;

wherein if the domain (A) comprises SEQ ID NO: 582 and domain (E) comprises SEQ ID NO: 580 they associate to form a binding site that binds the HIV-1 envelope like antibody DH514;

wherein if the domain (A) comprises SEQ ID NO: 586 and domain (E) comprises SEQ ID NO: 584 they associate to form a binding site that binds the HIV-1 envelope like antibody DH515;

wherein if the domain (A) comprises SEQ ID NO: 590 and domain (E) comprises SEQ ID NO: 588 they associate to form a binding site that binds the HIV-1 envelope like antibody DH516;

wherein if the domain (A) comprises SEQ ID NO: 594 and domain (E) comprises SEQ ID NO: 592 they associate to form a binding site that binds the HIV-1 envelope like antibody DH517;

wherein if the domain (A) comprises SEQ ID NO: 598 and domain (E) comprises SEQ ID NO: 596 they associate to form a binding site that binds the HIV-1 envelope like antibody DH518;

wherein if the domain (A) comprises SEQ ID NO: 602 and domain (E) comprises SEQ ID NO: 600 they associate to form a binding site that binds the HIV-1 envelope like antibody DH536; or wherein if the domain (A) comprises SEQ ID NO: 606 and domain (E) comprises SEQ ID NO: 604 they associate to form a binding site that binds the HIV-1 envelope like antibody DH537; or

wherein if the domain (B) comprises SEQ ID NO: 500 and domain (D) comprises SEQ ID NO: 502 they associate to form a binding site that binds CD3; or

wherein if the domain (B) comprises SEQ ID NO: 504 and domain (D) comprises SEQ ID NO: 506 they associate to form a binding site that binds CD16; and

the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0036] In certain aspects the invention provides a bispecific molecule comprising a first polypeptide chain, a second polypeptide chain, a third polypeptide chain, and a fourth polypeptide chain, wherein some of the polypeptides are covalently bonded, and wherein:

(I) the first and the third polypeptide chains each comprise in the N- to C-terminal direction:

(i) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VL1) having the binding specificity of a gp41 MPER binding antibody

(i) ;

(ii) a domain (B) comprising a binding region of a heavy chain variable domain of a second immunoglobulin (VH2) specific for an epitope (2);

(iii) a domain (C) comprising a heterodimer promoting domain; and

(iv) a CH2-CH3 domain;

(II) the second and fourth polypeptide chains each comprise in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2);

(ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VH1) having the binding specificity of a gp41 MPER binding antibody

(i);

(iii) a domain (F) comprising a heterodimer promoting domain; and wherein

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding antibody (1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0037] In certain aspects the invention provides such bispecific molecules wherein:

(i) domains (A) and (B) are separated by a peptide linker 1 ;

(ii) domains (C) and (B) are separated by a peptide linker 2;

(iii) the CH2-CH3 domain and domain (C) are separated by a peptide linker 3 or a spacer linker 3;

(iv) domains (D) and (E) are separated by a peptide linker 1 ; and

(v) domains (F) and (E) are separated by a peptide linker 2.

[0038] In certain aspects the invention provides a bispecific molecule comprising a first polypeptide chain, a second polypeptide chain, a third polypeptide chain, and a fourth polypeptide chain, wherein some of the polypeptides are covalently bonded, and wherein:

(I) the first and the third polypeptide chains each comprise in the N- to C-terminal direction:

(i) a domain (A) comprising a binding region of the light chain variable domain of a first immunoglobulin (VL1) having the binding specificity of the gp41 MPER binding antibody DH511.2, a variant of DH51 1.2 called DH51 1 2 K3, or any antibody of the DH51 1 lineage (1);

(iii) a domain (C) comprising a heterodimer promoting domain, wherein domains (C) and (B) are separated by a peptide linker 2; and

(iv) a CH2-CH3 domain, wherein the CH2-CH3 domain and domain (C) are separated by a peptide linker 3 or a spacer linker 3;

(II) the second and fourth polypeptide chains each comprise in the N- to C-terminal direction:

(i) a domain (D) comprising a binding region of a light chain variable domain of the second immunoglobulin (VL2) specific for the epitope (2); (ii) a domain (E) comprising a binding region of a heavy chain variable domain of the first immunoglobulin (VH1) having the binding specificity of the gp41 MPER binding antibody DH51 1.2, a variant of DH51 1.2 called DH51 1 2 K3, or any antibody of the DH51 1 lineage (1), wherein domains (D) and (E) are separated by a peptide linker 1 ;

(iii) a domain (F) comprising a heterodimer promoting domain, wherein domains (F) and (E) are separated by a peptide linker 2; and wherein

the domains (A) and (B) do not associate with one another to form an epitope binding site; the domains (D) and (E) do not associate with one another to form an epitope binding site; the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like the gp41 MPER binding antibody DH51 1.2, a variant of DH51 1.2 called DH51 1 2 K3, or any antibody of the DH51 1 lineage ( 1);

the domains (B) and (D) associate to form a binding site that binds the epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0039] In certain aspects said first and second polypeptide chains are covalently bonded to one another; said third and fourth polypeptide chains are covalently bonded to one another; and said first and third chains are covalently bonded to one another.

[0040] In certain aspects the invention provides a bispecific molecule comprising a first polypeptide chain, a second polypeptide chain, a third polypeptide chain, and a fourth polypeptide chain, wherein the first and second polypeptide chains are covalently bonded, the third and fourth polypeptide chains are covalently bonded, and the first and third chains are covalently bonded, and wherein:

(I) the first and the third polypeptide chains each comprise in the N- to C-terminal direction:

(i) a domain (A) comprising SEQ ID NO: 553, 570, 574, 578, 582, 586, 590, 594, 598, 602, 606, or 625;

(ii) a domain (B) comprising SEQ ID NO: 500 or 504;

(iii) a domain (C) comprising SEQ ID NO: 520, 521, 518, or 519; and

(iv) a CH2-CH3 domain comprising SEQ ID NO: 527, 528, or 529;

(II) the second and fourth polypeptide chains each comprise in the N- to C-terminal direction:

(i) a domain (D) comprising SEQ ID NO: 502, or 506;

(ii) a domain (E) comprising SEQ ID NO: 551, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608-624, or 626 (Table 4); (iii) a domain (F) comprising SEQ ID NO: 518, 519, 520, or 521 ; and wherein the domains (A) and (B) are linked so that they do not associate with one another to form an epitope binding site;

the domains (D) and (E) are linked so that they do not associate with one another to form an epitope binding site;

the domains (A) and (E) associate to form a binding site that binds the HIV-1 envelope like a gp41 MPER binding antibody (1);

the domains (B) and (D) associate to form a binding site that binds an epitope (2); and the CH2-CH3 domains of the first and third polypeptide form an Fc Domain.

[0041] In certain aspects the invention provides such bispecific molecules wherein:

(i) domains (A) and (B) are separated by SEQ ID NO: 508;

(ii) domains (C) and (B) are separated by SEQ ID NO: 509 or 510;

(iii) the CH2-CH3 domain and domain (C) are separated by SEQ ID NO: 523 or 522;

(iv) domains (D) and (E) are separated by SEQ ID NO: 508; and

(v) domains (F) and (E) are separated by SEQ ID NO: 509 or 510.

[0042] In certain aspects the invention provides a bispecific molecule comprising a first polypeptide chain, a second polypeptide chain, a third polypeptide chain, and a fourth polypeptide chain, wherein the first and second polypeptide chains are covalently bonded, the third and fourth polypeptide chains are covalently bonded, and the first and third chains are covalently bonded, and wherein:

(I) the first and the third polypeptide chains each comprise in the N- to C-terminal direction:

(i) a domain (A) comprising SEQ ID NO: 553, 570, 574, 578, 582, 586, 590, 594, 598, 602, 606, or 625;

(ii) a domain (B) comprising SEQ ID NO: 500 or 504, wherein domains (A) and (B) are separated by SEQ ID NO: 508;

(iii) a domain (C) comprising SEQ ID NO: 520, 521, 518, or 519, wherein domains (C) and (B) are separated by SEQ ID NO: 509 or 510; and

(iv) a CH2-CH3 domain comprising SEQ ID NO: 527, 528, or 529, wherein the CH2- CH3 domain and domain (C) are separated by SEQ ID NO: 523 or 522;

(II) the second and fourth polypeptide chains each comprise in the N- to C-terminal direction: (i) a domain (D) comprising SEQ ID NO: 502, or 506;

(ii) a domain (E) comprising SEQ ID NO: 551, 568, 572, 576, 580, 584, 588, 592, 596, 600, 604, 608-624, or 626 (Table 4), wherein domains (D) and (E) are separated by SEQ ID NO: 508;

(iii) a domain (F) comprising SEQ ID NO: 518, 519, 520, or 521, wherein domains (F) and (E) are separated by SEQ ID NO: 509 or 510; and wherein

the domains (A) and (B) do not associate with one another to form an epitope binding site; the domains (D) and (E) do not associate with one another to form an epitope binding site; wherein if the domain (A) comprises SEQ ID NO: 553 and domain (E) comprises SEQ ID NO: 551 they associate to form a binding site that binds the HIV-1 envelope like antibody DH511.2 K3;