Inhibition of PKCα and θ significantly ameliorates acute GVHD after myeloablative allogeneic BMT. Recipient BALB/c mice were lethally irradiated (800 cGy) and transplanted with 5 × 106 C57BL/6 TCD-BM cells alone (n = 6) or in addition to 1 × 106 total T cells from WT C57BL/6 donors and treated twice daily by gavage with vehicle (n = 15) or 40 mg/kg R524 (n = 12) beginning on day 0 (the day of BMT) and continuing daily for 6 weeks. Recipient mice were monitored throughout the experimental period for survival (A) and weight change (B), and pooled data from 3 separate experiments are represented. In separate experiments, recipients (n = 4 recipients per group per experiment) were euthanized 2 weeks posttransplant, and samples of skin, liver, lung, small intestine, and large intestine were collected in formalin for routine hematoxylin and eosin and scored for microscopic GVHD severity by a pathologist blinded to the treatment groups. Average scores for GVHD target organs across 3 separate experiments (C) are depicted. *P < .05; **P < .01; ***P < .001 (compared with vehicle-treated recipients). All error bars indicate SEM.
