POTENTIAL VIRAL VECTORS FOR THE STIMULATION OF MUCOSAL ANTIBODY-RESPONSES AGAINST ENTERIC VIRAL-ANTIGENS IN PIGS

Four viruses were compared for their ability to induce an intestinal a ntibody response in piglets. Antibodies were not detected in response to oral vaccination with either fowlpox virus or a baculovirUS (BV). S imultaneous oral dosing and parenteral inoculation with high concentra tions Of BV in an oil emulsion adjuvant induced high levels of circula ting virus neutralising (VN) antibodies, and also low levels of intest inal antibodies when booster doses of virus were given. In response to oral vaccination with swinepox virus (SPV), low levels of circulating and intestinal VN antibodies, and higher titres of antibodies reactiv e in an enzyme immunoassay, including intestinal antibodies of the IgA class, were detected. Oral vaccination with porcine adenovirus type 3 (PAV-3) stimulated both circulating and intestinal VN antibodies, and IgA antibodies were demonstrated in the intestinal contents. It was c oncluded that spv and PAV-3 might be suitable vectors for the expressi on of genes encoding the protective antigens of porcine enteric viruse s.