STUDIES OF CD4- CD8- ALPHA-BETA-BONE MARROW T-CELLS WITH SUPPRESSOR ACTIVITY

The predominant T cell subset in the bone marrow of specific pathogen-free C57BL/Ka and BALB/c mice expressed the alpha-beta+ TCR CD4- CD8- surface phenotype. Purified C57BL/Ka alpha-beta+ TCR CD4- CD8- marrow cells obtained by cell sorting suppressed the MLR of C57BL/Ka responder and BALB/c stimulator spleen cells. Although the percentage of typical T cells in the spleen was markedly reduced in adult nude mice or normal neonatal mice as compared to the normal adult, the percentage of alpha-beta+ TCR CD4- CD8- cells in the spleen and marrow was not. The percentage of "self-reactive" V-beta-5+ T cells in the BALB/c spleen was markedly reduced as compared to that in the C57BL/Ka spleen. However, the percentages in the bone marrow were similar. The results indicate that the predominant subset of marrow T cells in these pathogen-free mice differ with regard to surface marker phenotype, function, dependence on the adult thymus, and deletion of certain self-reactive V-beta receptors as compared to typical spleen T cells. The marrow T cells appear to develop directly from marrow precursors without rearranged beta-chain genes during a 48 hour in vitro culture.