BHV-1 glycoprotein 1 and recombinant interleukin 1 beta efficiently elicit mucosal IgA response

The mucosal immune response to most soluble antigens administered directly to the mucosal system is low and requires a large amount of antigen and frequent vaccinations. In this study we tested whether immunizing cattle at a site which shares lymphatic drainage with the nasal mucosa could prime local mucosal immunity. We further tested whether recombinant bovine IL-1 beta (rBoIL-1 beta) could potentiate the induction of mucosal immunity. Animals were immunized subcutaneously at the base of the ear (s.e.) with recombinant bovine herpesvirus-1 (BHV-1) envelope glycoprotein I (gI) (35 micrograms animal-1) emulsified in incomplete Freund's adjuvant with or without rBoIL-1 beta (500 ng kg-1) followed by a second immunization 42 days later. Animals were challenged with virulent BHV-1 intranasally 42 days after the second immunization. Mucosal IgA from the nares was induced after only one immunization, and enhanced by boosting. rBoIL-1 beta treated animals had higher levels of BHV-1 specific nasal IgA (p < 0.01) and serum neutralizing antibody (p < 0.05). rBoIL-1 beta-treated animals also had increased numbers of surface IgA+ (p < 0.05) and IgG1+ (p < 0.001) B cells after in vitro antigen (gI) stimulation of peripheral blood lymphocytes suggesting that there was a greater expension of IgA+ and IgG1+ B cells in rBoIL-1 beta treated animals. When challenged with BHV-1, 3 of 4 animals in the gI+rBoIL-1 beta group were fully protected from viral replication in the nares, while only 1 of 4 animals receiving gI alone was protected.(ABSTRACT TRUNCATED AT 250 WORDS)