Antibodies and T cells against synthetic peptides of the C-terminal domain (Hc) of botulinum neurotoxin type A and their cross-reaction with Hc

Seventeen peptides containing T cell and/or antibody (Ab) epitopes previously localized on H-c of botulinum neurotoxin type A were used in SJL and BALB/c mice as immunogens either individually or as an equimolar mixture of groups that contained epitopes of T cells, Abs or both, to determine their abilities to generate T cells and/or Abs that recognize intact H-c. In SJL, peptide 897-915 which included both T cell and Ab epitopes, elicited Abs that cross-reacted very strongly with H-c. In BALB/c, peptides 869-887, 883-901, 981-999 and 1275-1296 which contained Ab epitopes generated Abs that cross-reacted strongly with H-c. A mixture of peptides that contained T cell and Ab epitopes was effective in both strains in eliciting T cells and Abs that cross-reacted with H-c. This mixture form gave a quicker rise (after two injections) in cross-reactive (with H-c) Ab titer as compared to other peptide mixtures or the individual peptides, and sustained in BALB/c a high Ab titer upon further booster injections. Some of the regions that elicited crossreactive immunity to H-c have sequence similarity to other clostridial toxins, suggesting that one or more of these synthetic peptides might provide cross-protection against those toxins. (C) 1998 Elsevier Science B.V.