Specificity and cross-reactivity of synthetic peptides derived from a major antigenic site of influenza hemagglutinin.

A synthetic peptide corresponding to sequence 138-164 of influenza hemagglutinin elicited in rabbits antibodies that recognized different parts of the peptide, namely the loop region (139-146) and the rest of the peptide, region 147-164. This was shown both by direct binding and by competitive-inhibition experiments. Individual antisera differed in their specificity. The contribution of the Asp residue at position 144 to the antigenic specificity was shown in various inhibition assays. These data are in accordance with the reported effect of the exchange Gly----Asp on the serological specificity of influenza virus.