BHV-1 GLYCOPROTEIN-1 AND RECOMBINANT INTERLEUKIN-1-BETA EFFICIENTLY ELICIT MUCOSAL IGA RESPONSE

The mucosal immune response to most soluble antigens administered dire ctly to the mucosal system is low and requires a large amount of antig en and frequent vaccinations. In this study we tested whether immunizi ng cattle at a site which shares lymphatic drainage with the nasal muc osa could prime local mucosal immunity. We further tested whether reco mbinant 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) envel ope glycoprotein I (gI) (35 mu g animal(-1)) emulsified in incomplete Freund's adjuvant with or without rBoIL-1 beta (500 ng kg(-1)) followe d by a second immunization 42 days later. Animals were challenged with virulent BHV-1 intranasally 42 days after the second immunization. Mu cosal IgA from the nares was induced after only one immunization, and enhanced by boosting. rBoIL-1 beta treated animals had higher levels o f BHV-1 specific nasal IgA (p<0.01) and serum neutralizing antibody (p <0.05). rBolL-1 beta-treated animals also had increased numbers of sur face IgA+ (p<0.05) and IgG1(+) (p<0.001) B cells after in vitro antige n (gI) stimulation of peripheral blood lymphocytes suggesting that the re was a greater expension of IgA+ and IgG1+ B cells in rBoIL-1 beta c reated animals. When challenged with BHV-1, 3 of 4 animals in the gI-r BoIL-1 beta group were fully protected from viral replication in the n ares, while only I of 4 animals receiving gI alone was protected. Our novel findings suggested that immunization at sites that share lymphat ic drainage with mucosal surfaces is an efficient way for stimulating the mucosal IgA response. Furthermore, rBolL-1 beta can be a potent st imulator of this mucosal and systemic IgA production.