Figure 2. Increase in IL-12Rβ2 chain expression on naïve CD4 T cells occurs spontaneously and reaches a transitional level by day 8 after birth.

Naïve CD4 T cells were purified from DO11.10 mice at different time points after birth and assessed for IL-12Rβ2 expression at the protein (A) and mRNA (B) level by flow cytometry and real-time PCR, respectively. (A) The Zebra plots show IL-12Rβ2 protein and CD62L expression on KJ1-26⁺CD4⁺ T cells. For comparison purposes, IL-12Rβ2 expression was analyzed on CD4⁺CD11c^- IFNγ⁺ differentiated neonatal Th1 cells. (B) The bars represent the mean ± SD fold mRNA increase from 3 experiments based on the comparative threshold cycle (C_T). (C) Naïve CD4 T cells were isolated from 1d old DO11.10 mice and incubated with graded amounts of rIL-12 for 24h. The cells were then stained with KJ1-26, anti-CD4, anti-CD62L and anti-IL-12Rβ2 antibodies. The percentages of IL-12Rβ2⁺CD62L⁺ among total KJ1-26⁺-CD4⁺ T cells are indicated in the upper right corner of each quadrant. (D) Naïve CD4 T cells from 1d old IL-13Rα1-GFP reporter mice were stimulated with anti-CD3 (10 μg/mL), and anti-CD28 (1 μg/mL) for 5 days in the absence or presence of 1 ng/ml IL-12 and stained for CD4, CD11c, and intracellular IFNγ. The CD4⁺CD11c^-IFNγ⁺ Th1 cells were analyzed for IL-13Rα1 expression by GFP.