Analysis of the coverage capacity of the StreptInCor candidate vaccine against Streptococcus pyogenes.

a b s t r a c t Streptococcus pyogenes is responsible for infections as pharyngitis, sepsis, necrotizing fasciitis and strep- tococcal toxic shock syndrome. The M protein is the major bacterial antigen and consists of both polymorphic N-terminal portion and a conserved region. In the present study, we analyzed the in vitro ability of StreptInCor a C-terminal candidate vaccine against S. pyogenes to induce antibodies to neutral- ize/opsonize the most common S. pyogenes strains in Sao Paulo by examining the recognition by sera from StreptInCor immunized mice. We also evaluated the presence of cross-reactive antibodies against human heart valve tissue. Anti-StreptInCor antibodies were able to neutralize/opsonize at least 5 strains, show- ing that immunization with StreptInCor is effective against several S. pyogenes strains and can prevent infection and subsequent sequelae without causing autoimmune reactions.