Unlike that observed with BALB/c WT mice, infection of BALB/c STAT6 −/− mice with VV-HA-IL-4 compared to VV-HA control did not impair the IFN-γ and TNF-α cytokine production capacity of KdA5275–83 or KdF226–34 specific-CD8+ T cells (figure 8B and 8C). The gene discussed is IL4; the disease is infection.