The influence of maternal immunity on the development of the in vitro lymphocyte proliferation response against pseudorabies virus in pigs

In this study, the influence of maternal immunity against pseudorabies virus (PRV) on the development of a PRV-specific T-cell response in pigs was investigated. Pigs with or without maternal immunity were challenged by inoculation with wild-type PRV, or were vaccinated with 783 and subsequently inoculated. Peripheral blood lymphocytes, collected after vaccination and/or inoculation, were used for PRV-induced lymphocyte proliferation assays in vitro as a measure of a PRV-specific T-cell response. In unvaccinated pigs, the presence of maternal immunity did nor inhibit the development of a T-cell response after inoculation with PRV. In contrast, maternal immunity did inhibit the development of a PRV-induced response after intramuscular vaccination. Moreover, vaccinated pigs without maternal immunity shed virus for a shorter period after inoculation than vaccinated pigs with maternal immunity. The greater T-cell response induced by the vaccine might have contributed to the more rapid clearance of PRV in these pigs.