The protective immunogenicity of a hybrid peptide containing tandem copies of types 5 and 24 epitopes was investigated. Carboxy-terminal peptides of the cyanogen bromide-derived fragment 7 (CB7) of type 24 M protein were chemically synthesized, and then extended to include the first 20 residues of the amino-terminus of type 5 M protein. When emulsified in CFA and injected into rabbits without conjugation to a carrier, each of the synthetic hybrid peptides, designated S-M5(1-20)-S-CB7(23-35)C and S-M5(1-20)-S-CB(19-34), evoked opsonic antibodies against both types 5 and 24 streptococci without raising heart tissue-crossreactive immunity. These results suggest that tandem hybrid peptides may provide a new approach to the development of multivalent vaccines, not only to different serotypes of group A streptococci but perhaps also to a variety of other infectious agents.
Antibodies produced by B cells are highly specific for antigen as a result of random gene recombination and somatic hypermutation and affinity maturation. As the main effector of the humoral immune system, antibodies can neutralize foreign cells. Find the latest research on antibody specificity here.