SOCS3^−/ΔLck T cells exhibit dysregulated cytokine production after allogeneic SCT. Splenocytes from G-CSF–treated WT or SOCS3^−/ΔLck mice were transplanted into lethally irradiated (1100 cGy) B6D2F1 recipient mice, and at day 7 after transplantation splenocytes were examined for cytokine production. (A) Splenocytes were cultured for 24 hours with soluble CD3, and supernatants were collected and assayed for cytokines by cytometric bead array. Data represent mean ± SEM of pooled results from 2 similar experiments (n = 10 animals/group). Black bars and white bars represent G-CSF–treated WT or SOCS3^−/ΔLck mice, respectively. (B) After 4-hour culture with phorbol myristate acetate and ionomycin, cell cytokine production was analyzed by intracellular cytokine staining with 4-color flow cytometry. Numbers in quadrants represent the percentage of gated CD4 or CD8 T cells as indicated.