BALB/c mice showed elevated levels of IgG1, correlating with the high production of IL-4 observed in their CD4+ T cells, while sera from KRT14CreIL-4Rα−/lox and control mice did not show significant IgG1 levels (Figure 3F), in line with the absence of Th2 cells detected in dLN and at the site of infection. The gene discussed is CD4; the disease is infection.