IL4 and infection: 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.