IL2 and infection: Comparing the expression of TNF-α, IFN-γ and IL-2 among CD4/10.4 and CD8/10.4 T cells at an early and late time point showed that whereas both populations contained polyfunctional T cells at early stages of infection, only CD4/10.4 maintained a substantial part of the cell population as polyfunctional T cells (Fig. 5A–C).