Murine acute graft-versus-host disease can be prevented by depletion of alloreactive T lymphocytes using activation-induced cell death

Abstract

Depletion of T lymphocytes from allogeneic bone marrow transplants successfully prevents the development of graftversus-host disease (GvHD) but is associated with impaired engraftment, immunosuppression, and abrogation of the graft-versus-leukemia effect. We therefore explored the possibility of selectively eliminating alloreactive T cells by CD95/CD95L-mediated activation-induced cell death (AICD) in a major histocompatibility complex allogeneic murine model system. Activation of resting or preactivated T lymphocytes from C3H/HeJ (H-2k) mice was induced with irradiated BALB/cJ (H-2d) mouse-derived stimulators. Substantial decrease (≥ 80%) of proliferative and lytic responses by activated alloreactive T cells was subsequently achieved by incubating the mixed lymphocyte culture with an agonistic monoclonal antibody to CD95, and residual T cells recovered did not elicit alloreactivity upon challenge to H-2d. Depletion of alloreactive T lymphocytes by AICD was specific because reactivity to an I-Ad-restricted ovalbumin (OVA) peptide by OVA-specific CD4+ T cells mixed into the allogeneic T-cell pool and subjected to induction of AICD in the absence of OVA peptide could be preserved. Adoptive transfer of donorderived allogeneic T lymphocytes, depleted from alloreactive T cells by AICD in vitro, in the parent (C3H/He) to F1 (C3H/He × BALB/c) GvHD model prevented lethal GvHD. The results presented suggest that alloreactive T cells can effectively be depleted from allogeneic T cells by induction of AICD to prevent GvHD and might introduce a new strategy for the separation of GvH-reactive T cells and T cells mediating antiviral and possibly graft-versus-leukemia effects. © 2002 by The American Society of Hematology.