Suppression of cytotoxic T-cell generation by natural suppressor cells from mice with GVHD is partially reversed by indomethacin.

Natural suppressor cells from the spleens of mice with graft-versus-host disease produced across minor histocompatibility barriers inhibit the in vitro generation of alloreactive cytotoxic T lymphocytes by spleen cells from normal mice. The mechanism of natural suppression was studied; suppression does not require direct cell contact with targets. Exogenous interleukin-2 has no effect in reversing suppression while indomethacin partially reverses the suppression mediated by natural suppressor cells.