Evaluation of the immunogenicity and protective efficacy of a recombinant CS6-based ETEC vaccine in an Aotus nancymaae CS6 + ETEC challenge model

Colonization factors or Coli surface antigens (CFs CS) are important virulence of Enterotoxigenic E. coli (ETEC) that mediate intestinal colonization and accordingly targets vaccine development efforts. CS6 is a highly prevalent CF associated with symptomatic ETEC infection both in endemic populations amongst travelers. In this study, we used an Aotus nancymaae non-human primate challenge model + strain, B7A, to test the immunogenicity protective efficacy (PE) recombinant CS6-based subunit vaccine. Specifically, determined ability dscCssBA, donor strand complemented stabilized fusion two subunits fimbriae, CssA CssB, elicit protection against mediated diarrhea when given intradermally (ID) genetically attenuated double mutant heat-labile enterotoxin LT(R192G/L211A) (dmLT). ID vaccination dscCssBA dmLT induced strong serum antibody responses LT. Importantly, resulted no observed diarrheal disease (PE = 100%, p 0.03) following B7A as compared PBS immunized animals, attack rate 62.5%. These data demonstrate potential role may play antigen can provide homologous model. Combined, these indicate CS6, more specifically, engineered derivative should be considered for further clinical development.