Modulation of immune response to group C meningococcal conjugate vaccine given intranasally to mice together with the LTK63 mucosal adjuvant and the trimethyl chitosan delivery system.

Previous work had shown that the immunogenicity of conjugate vaccine against group C meningococci (CRM-MenC) is enhanced when it is delivered intranasally (inl) with mucosal adjuvants, such as mutants of the Escherichia coli enterotoxin (LT), and with delivery systems such as chitosan derivatives. We show, in mice, that the concomitant use of limiting doses of the fully nontoxic LTK63 mutant as a mucosal adjuvant and of the trimethyl derivative of chitosan as a delivery system allows the reduction of each of the components for the induction of antibody and bactericidal responses to CRM-MenC conjugate vaccine delivered inl at titers similar to or higher than those induced by parenteral immunization. These data could affect the design of efficacious mucosal vaccines and their safety.