Monoclonal antibodies to hepatitis B surface antigen (HBsAg) with anti-a specificity recognize a synthetic peptide analogue (S135 155) with unmodified lysine (141

Peptides ynthesized for potential application as antiviral vaccines have been mostly tested in the form of conjugates with carrier proteins. The possible use of several distinct synthetic vaccines in prophylaxis would be facilitated by the availability of fully synthetic immunogens. A synthetic peptide corresponding to residues 135 to 155 (P135-155) of hepatitis B surface antigen (HBsAg) failed to elicit in free form anti-peptide antibodies or anti-HBs. However, polymers of P 135-155 (prepared by linking to diaminoalkanes) and synthetic onjugates prepared by binding P135-155 to liposomes or polylysine were immunogenic. A poor correlation was observed between anti-peptide and anti-HBs responses licited by these conjugates. Glutaraldehyde-fixed liposomes appeared to be the carriers of choice for inducing anti-HBs. The generation of antibodies to proteins by immunization with short peptides having the amino acid sequence corresponding to the sequence of preselected protein fragments appears to be a frequent event (Niman et al., 1983). Nevertheless, the elicitation of antibodies with a high binding constant for the native protein may depend on the appropriate stable conformation of the synthetic peptide immunogen (Pfaff et al., 1982; Neurath et al., 1982; Ionescu-Matiu etal.