Intranasal immunization with tetanus toxoid and CNF1 as a new mucosal adjuvant protects BALB/c mice against lethal challenge

Although often requiring the development of efficient adjuvants, needle-free mucosal delivery of vaccine is of major interest as a strategy of mass immunization against infectious diseases. We report that mucosal immunization against tetanus toxoid through nasal route, together with active cytotoxic necrotizing factor 1 (CNF1), elicits a specific and long lasting anti-tetanus toxin response, comprising seric IgG and IgA, as well as mucosal IgA. Immunized mice were protected against a challenge with lethal doses of tetanus toxin (10 × LD50). The Rho GTPase activating toxin CNF1 is thus an attractive mucosal adjuvant candidate for nasal vaccines.