Chemokine expression by GVHD-inducing T cells.

T cells from bm1 donors were transferred into irradiated MIP-1α^−/− recipients. Ten days after transfer, the recipient mice were killed, and the splenoctyes were removed, selected for CD8⁺ cells, and stimulated twice in vitro with irradiated (2500 cGy) MIP-1α^−/− splenocytes. The isolated T cells were then incubated with bone marrow–derived macrophages from MIP-1α^−/− B6 or bm1 mice. The supernatants were harvested after 24 hours, and RNA was prepared from the cells as indicated. Lane 1: Macrophages from MIP-1α^−/− mice; Lane 2: macrophages from bm1 mice; Lane 3: T cells incubated with syngeneic bm1 macrophages; and Lane 4: T cells incubated with class I disparate MIP-1α^−/− B6 macrophages. Enhanced expression is found for RANTES, MIP-1β, and MIP-1α in the presence of an antigen (compare expressions in lane 3 vs lane 4).