Reduction of fatal graft-versus-host disease by 3H--thymidine suicide of donor cells cultured with host cells

The effect of the tritiated thymidine (3H-TdR) suicide technique on the ability of donor cells to induce fatal graft-versus-host disease (GVHD) was studied. C57BL/6 (H-2/sup b/) spleen cells were stimulated in vitro with irradiated BALB/c (H-2/sup d/) Moloney lymphoma cells in mixed culture and 3H-TdR of high-specific activity added to eliminate proliferating cells. The ability of such cells to induce fatal GVHD was assayed by injecting them i.v. into adult BALB/c mice immunosuppressed with cyclophosphamide (180 mg/kg). These cells induced fatal GVHD in fewer mice (52 percent) than did C57BL/6 cells cultured with BALB/c lymphoma cells but without 3H-TdR (87 percent) and C57BL/6 cells cultured with irradiated C57BL/6 cells with (95 percent) or without 3H-TdR (86 percent). Thus, the 3H-TdR suicide technique greatly diminished the ability of cells to induce lethal GVHD