In Exp 2, H3N2-specific CD4+ and CD8β+ T-cell responses in BALCs were also higher but not significantly so after PRRSV-2/H3N2 co-infection (mean of 1.71% vs. 0.90% within CD4+ T cells and 0.54% vs. 0.36% within CD8β+ T cells, Figure 4B). The gene discussed is CD4; the disease is coinfection.