ADJUVANT ACTIVITY OF THE HEAT-LABILE ENTEROTOXIN FROM ENTEROTOXIGENICESCHERICHIA-COLI FOR ORAL-ADMINISTRATION OF INACTIVATED INFLUENZA-VIRUS VACCINE

Alternative strategies for vaccination against influenza that elicit b oth systemic antibody and mucosal IgA responses are needed to improve the efficacy in protection against infection, This study demonstrated that oral delivery of inactivated influenza vaccine with the heat-labi le enterotoxin (LT) from enterotoxigenic Escherichia coli elicited the spectrum of humoral and cell-mediated responses in BALB/c mice critic al for the protection and recovery from influenza virus infection, Coa dministration of LT with oral influenza vaccine increased antiviral se rum IgG and mucosal IgA responses compared with administration of oral influenza vaccine alone, Serum hemagglutination-inhibition and neutra lizing antibodies were also augmented by LT, The adjuvant potentiated protection from infection with influenza A H3N2 viruses in mouse lower and upper respiratory tracts, enabling the use of lower doses of oral vaccine, Coadministration of LT with oral inactivated influenza vacci ne induced influenza virus-specific proliferative T cells, interleukin -2 production, and major histocompatibility complex class I-restricted cytotoxic T cells.