CD4 and infection: To further assess which CD4+ T cell subpopulation might be mainly responsible for the IL-10 production, TIGER IL-10 reporter mice were analyzed for GFP expression on day 10 post infection in TFH and TH1 cells using PSGL1 and Ly6C as surrogate markers (with PSGL1+ Ly6C+ CD4+ T cells representing TH1 cells and PSGL1− Ly6C− cells representing TFH cells; Figure S7A–F).