Analysis of murine T lymphocyte markers during the early phases of GvH-associated suppression of cytotoxic T lymphocyte responses.

Abstract

Graft-vs-host- (GvH) associated immune-suppression was generated by injecting nonirradiated (B6 X C3H)F1 hybrid mice with 40 to 60 X 10(6) B6 or C3H parental spleen cells. Susceptibility to suppression as well as the potential of parental donor lymphocytes to generate suppressor activity was investigated in allogeneic cytotoxic T cell responses by mixing spleen cells from the inoculated F1 recipients with syngeneic responder cells from untreated mice. The susceptibility to suppression in F1 recipients, as well as the potential of parental lymphocytes to induce suppression in F1 mice, varied with the age of the mice. Cellular analysis revealed that GvH-suppression was mediated by 500 R radiosensitive parental T cells during the period tested (from day 5 until day 8 after injection of B6 parental spleen cells). In contrast, selected F1 lymphocytes from recipients injected with parental spleen cells failed to exhibit suppressor cell activity. The sensitivity of parental GvH suppressor cells to anti-Lyt reagents was time dependent. Thus, suppressor cells were sensitive to monoclonal anti-Lyt-1 or anti-Lyt-2 and C (usually until day 7 after injection of parental spleen cells); subsequently, suppression became insensitive to anti-Lyt-1, but remained sensitive to anti-Lyt-2 and C treatment.