Cultured MDSC-IL-13 enhance GVHD survival in an arginase-1-dependent fashion. Lethally irradiated BALB/c recipients were given 107 B6 BM cells plus 2 × 106 purified CD25-depleted T cells plus either 2 × 106 MDSC-IL-13 or 6 × 106 MDSC-IL-13, both IL-13-treated. Kaplan-Meier survival curve of transplanted mice (A). Data represent 2 pooled experiments (BM only, N = 18; BM + T, N = 18; BM + T + 2 × 106 MDSC IL-13-tx, N = 22; BM + T + 6 × 106 MDSC- IL-13, N = 22; BM + T vs 2 × 106 MDSC IL-13, P < .001; BM + T vs 6 × 106 MDSC IL-13, P < .001; 2 × 106 MDSC IL-13 vs 6 × 106 MDSC- IL-13, P = .06). (B) Corresponding weights. (C) Kaplan-Meier survival curve of BM transplantation using 6 × 106 MDSC IL-13 generated from either WT mice or arginase-1 KO mice. Data represent one experiment (BM only, N = 8; BM + T, N = 12; BM + T + 6 × 106 WT MDSC-IL-13, N = 12; BM + T + 6 × 106 arginase-I KO MDSC-IL-13, N = 12; BM + T vs 6 × 106 WT MDSCs, P = .05; BM + T vs 6 × 106 arginase-I KO MDSC-IL-13, P = .08; arginase-1 KO MDSC-IL-13 vs WT MDSC-IL-13, P = .1). (D) Corresponding weights.
