Administration of sGARP decreases effector cytokine production in vivo. Rag2^−/−γc^−/− mice (6 mice per group) were injected with 5 × 10⁶ PBMC and were treated either 3 times with 5 µg sGARP every other day starting from day 1 or were left untreated. (A) On day 7 after treatment initiation, human T cells were reisolated from the spleens. sGARP administration decreased the infiltration with human CD45⁺ cells while increasing the frequency of CD4⁺CD25⁺Foxp3⁺ T cells (relative ratio and absolute Treg number, horizontal bars represent mean values, n = 6, **P < .01, *P < .05; upper panel). sGARP shifted CD4⁺ T cells from central (CD45RO⁺CD27⁺) to effector memory cells (CD45RO⁺CD27^–). Dot blots (lower panel) show one representative result of 3 independent experiments (17.6% ± 5.9 and 28.9% ± 3.7 in the absence and presence of sGARP, respectively, n = 3). (B) sGARP reduces the number of IL-2 and IFN-γ–producing CD4⁺ T cells without affecting IL-17 production. Intracellular cytokine staining of reisolated human T cells on day 7 after treatment initiation was performed. Numbers of cytokine-producing cells (relative ratio and absolute numbers) in 6 individual mice (mean ± SEM, *P < .05) are shown. (C) GPT serum levels of mice from different treatment groups analyzed 20 days after PBMC transfer (8 mice per group, mean ± SEM, *P < .05).