Characterization of antigenic determinants on human myeloid colony forming cells with monoclonal antibodies.

Immunologic characterization of myeloid progenitor cells (CFUGM) provides a new dimension for identification and separation of this hemopoietic cell population from other cells within marrow and peripheral blood. Monoclonal antibodies against human anti Ia-like (HLA-DR) determinants and against T lymphocytes were utilized to more precisely define the cell surface antigenic structure of human CFUGM. Complement-mediated cytotoxicity testing demonstrated the presence of HLA-DR antigens and absence of a T lymphocyte antigen on the clonogenic CFUGM. Similar degrees of cytotoxicity were noted for B lymphocytes and CFUGM using anti HLA-DR monoclonal antibodies. Our studies with the anti T lymphocyte antibody suggest that T lymphocytes may be selectively removed from marrow cells without depletion of myeloid precursor cells.