CD8A and coinfection: In the Vac group, PRRSV-2/H3N2 co-infection induced a proportion of IFN-γ+ CD8+ T cells (mean 0.23%) and a significantly greater proportion of TNF+ CD8+ T cells (mean 0.35%) compared to Vac + PRRSV-2 (mean 0.02%; p<0.5).