On day 4 after infection, we found that higher frequencies of IL-10/GFP+ cells were NK1.1+ TCRβ− (NK cells), as compared to NK1.1+ TCRβ+, NK1.1− TCRβ−, and NK1.1− TCRβ+ cells (NK cells 56%±3% compared to NK1.1+ T cells: 5%±1%, and non-NK non T cells: 12%±1%, and T cells: 27%±2%) (Fig. 2C). This evidence concerns the gene IL10 and infection.