A donor-derived asialo-GM1+ cell induces depression of B-cell genesis during systemic graft-versus-host disease

The nature of the effector cell(s) responsible for the depression of B- cell genesis in the bone marrow of mice undergoing systemic graft- versus-host disease (GVHD) has been examined. Donor C57BL/6 (B6) mice were treated in vivo with either a single injection of anti-asialo GM1 antibody (anti-ASGM1) to eliminate naturally occurring (endogenous) ASGM1+ cells or B6xAF1 (B6AF1) lymphoid cells followed by anti-ASGM1 to eliminate both endogenous and “induced” ASGM1+ cells. Lymphoid cells from donor mice after the elimination of endogenous ASGM1+ cells produced severe GVHD and concomitant depression of B-cell genesis when injected into B6AF1 recipients. In contrast, cells from donors depleted of both the endogenous and inducible ASGM1+ populations did not cause GVHD or depletion of B lineage cells in B6AF1 recipients but did depress B-cell genesis in B6C3F1 mice. The “induced” ASGM1+ cells were Thy 1+, but their elimination did not significantly alter either overall T-cell function or specific cytotoxic T-cell (CTL) reactivity against the sensitizing (B6AF1) strain. The results suggest that the effector cell responsible for the depression of B-cell genesis during systemic GVHD can be induced to express ASGM1, is strain-specific and Thy 1+; but is not a conventional CTL.