OBJECTIVETo explore a new method of alleviating graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (allo-BMT) through selected elimination of mouse alloreactive T cells (ARTC) by Fas-Fas ligand (FasL) passway.

METHODSThe Sca-1(+) early hematopoietic cells (EHCs) were isolated from BALB/c mouse (H-2(d)) bone marrow mononuclear cells (BMMC) by using a high gradient magnetic cell sorting system (MACS), then transferred with exogenous mouse FasL (mFasL) gene by retroviral gene transfecting technique. Afterward the transduced EHCs were expanded in vitro for one week followed by coculture with the spleen cells from BAC mouse (H-2(d) x b) as one-way mixed lymphocyte culture (OWMLC) for 6 days, then the cytotoxicity of treated BAC mouse spleen cells against Na(2)(51)CrO(4) labelling spleen cells from BALB/c mouse was observed.

RESULTSThe Sca-1(+) EHCs were successfully isolated by MACS, with a purity of (89.0 +/- 6.1)%. After transferred with exogenous mFasL gene and expanded for one week, the transferred EHCs in the 6 day OWMLC with the spleen cells from BAC mouse at a ratio of five to one resulted in an obvious inhibition of the BAC mouse spleen cells cytotoxicity against the BALB/c mouse spleen cell at different effector/target ratios as compared to the control group (P < 0.01).

CONCLUSIONThe higher exogenous mFasL-expressing mouse EHCs can deplete ARTC against their own major histocompatibility complex (MHC) antigens in vitro.