RECOMBINANT, OCTAVALENT GROUP-A STREPTOCOCCAL M-PROTEIN VACCINE

One of the major obstacles to the development of group A streptococcal M protein vaccines is the multiplicity of M serotypes expressed by th ese organisms. In this study, we have constructed a recombinant, hybri d M protein that contains type-specific amino-terminal fragments of ei ght different M proteins. We show that the purified hybrid recombinant protein is immunogenic in rabbits and evokes antibodies that react,vi th native M proteins from the respective streptococcal serotypes. In a ddition, the immune sera evoked by the octavalent protein opsonized si x of the eight serotypes of streptococci, indicating that the majority of the M protein fragment contained protective epitopes that retained their native conformations in the hybrid protein. None of the antiser a raised against the octavalent protein crossreacted with human heart tissue. These studies indicate that multivalent, hybrid M proteins may be used to elicit broadly protective immune responses against multipl e serotypes of group A streptococci. Published by Elsevier Science Ltd .