Figure 5.

Normal Th1 cell differentiation in IL-31Rα^−/− mice. (A) Purified CD4⁺ T cells from WT and IL-31Rα^−/− mice were CFSE labeled and stimulated with plate-bound anti-CD3/anti-CD28 under Th1-polarizing conditions. Cells were assayed for proliferation and cytokine production by flow cytometry. The top number indicates the percentage of proliferating CD4⁺ T cells producing IFN-γ and the bottom number in italics is the percentage of CFSE-dim cells. (B) cDNA from purified naive CD4⁺ T cells cultured under Th1-polarizing conditions was subjected to real-time PCR analysis for IFN-γ expression relative to actin. (C) Supernatants from the cultures in A were assayed by ELISA for IFN-γ levels. (D) WT and IL-31Rα^−/− mice were infected with L. major promastigotes in the hind footpad. Lesion size was determined by measuring swelling of the infected footpad and subtracting that of the uninfected contralateral footpad. (E) Parasite load in the footpad was quantified by limiting dilution analysis at 12 wk after infection. Values represent the mean ± SEM for three mice per group. (F) Cells from the draining lymph nodes of L. major– infected WT or IL-31Rα^−/− mice were restimulated with soluble L. major antigen and analyzed by flow cytometry. Plots are gated on CD4⁺ cells and the number in the box indicates the percentage of CD4⁺ T cells producing IFN-γ.