Fig. 3. IL-7 is required for TH1 cell expansion from 2D2 naïve CD4+ T cells.
(A) Clinical scores (upper) and body weight (BW) (bottom) are shown for MOG-immunized wild-type B6 mice treated with IL-7 (1 μg) or vehicle control every 3 days starting from day 7 before symptom onset. (B to D) Frequency of CD4+ T lymphocytes expressing IFN-γ and IL-17. Sorted naïve CD4+ T cells from naïve 2D2 mice were activated in the presence of MOG(35–55) and irradiated antigen-presenting cells plus the respective cytokines for TH1 (upper) or TH17 (bottom) polarization. (B) During the differentiation period, cells were cultured in the presence or absence of IL-7 for 3 days. (C to D) In a separate experiment, after 3 days of culture in the presence of TH1- or TH17-polarizing conditions, cells were rested for 48 hours followed by restimulation with MOG(35–55) in the presence of different cytokines (for example, IL-12, IL-7, IL-23, or medium only as indicated above each individual FACS plot) during the expansion period. CD4+ T cells were analyzed for IFN-γ and IL-17 production by flow cytometry. The mean percentage ± SEM (n = 2 experiments) of cytokine-positive cells is given. Each experiment comprised four mice per group. Statistics were generated with Student's t test. *P < 0.05; **P < 0.01.