Effect of vaccination with a modified-live porcine reproductive and respiratory syndrome virus vaccine on dynamics of homologous viral infection in pigs.

Objective: To determine effects of vaccination protocols with modified-live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine on persistence and transmission of virus in pigs infected with a homologous isolate and determine clinical and virologic responses following heterologous viral challenge.

Animals: Four hundred forty 6- to 8-week-old PRRSV-naïve pigs.

Procedures: Pigs were allocated into 5 groups.

Beta-glucan enhancement of T cell IFNgamma response in swine.

Beta-glucan has been shown to enhance anti-tumor and anti-infection functions in animals. Pigs at 4 months of age were infected with porcine reproductive and respiratory syndrome virus (PRRSV), and peripheral blood monocytes (PBMC) were isolated for the detection of interferon gamma (IFNgamma)-producing cells. We found that soluble high molecular weight beta-glucan could increase IFNgamma-producing cell frequency in a dose-dependent manner in the enzyme-linked immunospot assay (ELISPOT) in the absence of antigenic restimulation.