Suppressor activity in the supernatant of T cell clones derived from chimeric mouse spleen cells

The supernatant from cultures of T cell clones derived from (BALB/c----C3H/He) chimeras suppresses BALB/c anti-C3H/He or BALB/c anti-C57BL/6 MLRs. When we studied the alloantigen specificity of the suppressor activity in culture supernatant, we observed three types of the suppressor activity (i.e., the suppressor activity against BALB/c anti-C3H/He MLR, against BALB/c anti-C57BL/6 MLR, and against both MLRs) on day 3 after stimulation of the T cell clones with 20% crude IL2 and feeder cells. Since the alloantigen specificity fluctuated somewhat with time, we considered that a time-course study was needed to determine it correctly. We thought it unlikely that any IFN-gamma or PGE2 in the culture supernatant of the T cell clones would have mediated the suppression. Our results suggest that alloantigen specific and non-specific suppressor T cells exist in bone marrow chimeras. The former appears to play an important role in inducing and maintaining transplantation tolerance, while the latter seems to have a rather harmful effect upon chimeras.