Role of IL-17 in the mucosal adjuvant activity of cholera toxin for epicutaneous vaccines (134.53)

Abstract

Abstract It is now established that the mucosal adjuvant activity of cholera toxin (CT) involves the induction of IL-1 and other proinflammatory cytokines. Interleukin-17 (IL-17) is a cytokine implicated in the regulation of inflammation. In addition, Th-17 associated cytokines TGF-beta and IL-6 act as Ab mu to alpha class switch factor and promote the terminal differentiation of B cells into plasma cells, respectively. We examined the role played by IL-17 in the mucosal adjuvant activity of CT for epicutaneous vaccines. Groups of IL-17 KO and control C57BL/6 mice were immunized by epicutaneous application of 50 micrograms of CT with 1 mg ovalbumin (OVA). Control mice developed high levels of OVA- and CT-specific IgA Abs in the serum, and in fecal extracts. The adjuvant activity of CT in control mice also resulted in high antigen-specific IgG responses in the serum with a profile of IgG subclasses characterized by a IgG1>IgG2a. The IL-17 KO mice given the same epicutaneous vaccine exhibited enhanced serum and fecal IgA responses. On the other hand, serum IgG responses were of the same magnitude and profile than control littermates, suggesting that IL-17 signaling affects CT-induced IgA but not IgG Abs.