Figure 5.

Addition of exogenous IL-1β, IL-18, and/or IL-33 disproportionately increases RTE proliferation and cytokine production in vitro. 10⁵ naive polyclonal CFSE-labeled CD4 RTEs or MN T cells were cultured for 2–6 d with 2 × 10⁵ irradiated TCRβ/δ^−/− splenocytes and 50 ng/ml soluble anti-CD3 with or without 30 ng/ml IL-1β, IL-18, and/or IL-33. (A) Histograms show representative CFSE dilution by RTEs (shaded) and mature T cells (open) after 2 d of culture under the indicated conditions. Bar graph data show a ratio of the percentages of RTEs to mature T cells dividing two or more times; data are presented as mean ± SEM and are compiled from two independent experiments. (B) After 5–6 d of culture, cells were restimulated with PMA and ionomycin and stained for intracellular IL-2. Numbers in the top left and top right dot plot quadrants represent the percentage of IL-2⁺ divided and nondivided cells, respectively. Data in the right panel are presented as mean ± SEM and are compiled from two independent experiments. Numbers in parentheses indicate the fold change for the indicated condition relative to stimulation with anti-CD3 alone. *, P < 0.05, by unpaired Student’s t test.