IL-21R KO CD4 T-cell IFN-γ and TNF-α are maintained in the spleen but reduced in MLNs. Lethally irradiated BALB/c mice were transplanted with B6 BM-TCD and WT or IL-21R KO T cells (1 × 10⁶). (A) MLNs and (B) spleens were harvested 1 week after BMT and stained for intracellular cytokine FACS analysis of donor CD4 T cells. Shown are combined data from 4 independent experiments with 20 total recipients per group. **P < .01 and ***P < .001 for WT versus KO T cells.