MHC class II and c-kit expression allows rapid enrichment of T-cell progenitors from total bone marrow cells

Abstract

T-cell progenitors in the embryonic bone marrow express the tyrosine kinase receptor c-kit. RR5, an anti-MHC class II β chain monoclonal antibody, subdivides this c-kit positive population. Intrathymic transfer experiments showed that most of the T-cell progenitors belong to the MHC class II+/c-kit+ bone marrow population in the embryo and young adult. On transplantation, these bone marrow progenitors lose this expression and differentiate into CD4 CD8 T lymphocytes. In contrast, erythroid progenitors are restricted to the MHC class II−/c-kit+ population. The MHC class II+/c-kit+ pro-T cells are metabolically active, because they stain brightly with rhodamin 123. Their cyclin A and B expression level suggests that they are in the mitotic phase of the cell cycle. Thus, we define an easy sorting protocol, which allows enrichment of T-cell progenitors from total bone marrow hemopoietic cells.