The capacity of MAPCs to delay GVHD mortality and limit target tissue destruction is dependent on anatomic location of the cells and their production of PGE2. BALB/c mice were lethally irradiated and then given 106 BM cells from B6 mice on day 0, followed by 2 × 106 purified CD25-depleted whole T cells on day 2. On day 1, mice were given 5 × 105 untreated B6 MAPCs or PBS delivered via IC injections. Kaplan-Meier survival curve is representative of 1 experiment in which BM only and BM plus T group had n = 6, and MAPC group had n = 8 (A). (B) BMT was performed as in panel A, except mice were given PBS or 5 × 105 MAPC IS on day 1. The survival curve is representative of 3 pooled experiments (BM only, n = 18; BM + T, n = 20; MAPCs, n = 26; MAPCs vs BM + T, P < .001). (C) Survival curve representative of 1 experiment in which mice received BMT plus untreated MAPCs or MAPCs pretreated overnight with indomethacin before IS injection (BM only, n = 5; BM + T, n = 5; MAPCs, n = 10; MAPC indo, n = 10; MAPCs vs MAPC indo, P = .002). Tissue taken from cohorts of mice from panel B was harvested on day 21 and embedded in OCT, followed by freezing in liquid nitrogen. Sections (6 μM) were stained with hematoxylin and eosin and analyzed for histopathologic evidence of GVHD. Representative images are shown. (D) Magnification × 200. (E) The average GVHD score for BM only, BM plus T, and BM plus T plus MAPC (IS) cohorts is shown. (F) Spleens were harvested from BMT plus MAPC IS transplanted mice on day 21 and snap frozen in OCT compound. Tissue sections were cut and stained using anti-luciferase and anti-PGE synthase antibodies. Confocal analysis reveals that MAPCs are found in the spleen at this time point and retain their ability to produce PGE2. (F) Top shows luciferase alone, and bottom shows colocalization of PGE synthase with luciferase.
