Figure 3.

Effector CD4 T cells co-producing IFNγ are the primary source of IL-10 during flu infection. (A) WT mice were treated with depleting or isotype control antibodies and infected with 1 LD₅₀ A/PR8. On d7, lungs were analyzed for IL-10 expression (n=5, and * = P < 0.05). (B) 2×10⁶ naïve HNT.Thy1.1 CD4 T cells were transferred to WT hosts then infected with 1 LD₅₀ A/PR8, and IL-10⁺ donor cells determined by ICCS on d7 (n=5). (C) Representative examples of donor cell IL-10/IFNγ and isotype staining +/− peptide stimulation. (D) Stated numbers of donor cells were transferred and ICCS performed as in (C); the ratio of IFNγ⁺/IL-10⁻ to IFNγ⁺/IL-10⁺ donor cells in lungs is shown (n=3). (E) Representative example of IL-10/IFNγ staining gated on CD4 T cells from DLN and lung of WT mice in the absence of adoptive transfer. (F) CD25/FoxP3 staining of host and donor lung CD4 T cells on d 7 post-infection. (G) Total IL-10⁺ T cells from FoxP3.GFP mice were separated on the basis of GFP expression (* = P < 0.05). Data is representative of 2 independent exp for A, D, G and greater than 5 for B, C, E, F.