PURPOSE: To produce the new conjugate antigen covalent with a carrier protein via specified D-glucosammine disaccharide as a binder and useful as vaccines for preventing septic shock caused by bacterial endotoxins.

CONSTITUTION: D-glucosammine disaccharide expressed by the formula I (R1 is H or acyl; R2, is 1-4C alkyl; P1 is H or phosphate; P2 is H, propyl, allyl or phosphate) is brought to react with a molecule (such as adipic acid bis- succinimizilester or the like) contg. two functional groups in which either is the one capable of reacting with the primary amine of this compd. and the other is the one capable of reacting with a carrier protein, and this reaction product is brought to react with a carrier protein to obtain the objective immunogenic conjugate expressed by the formula II [(n) is an integer from 1 to 30); and Q is a carrier protein or peptide] and useful as vaccines for preventing septic shock caused by bacterial endotoxins.