Differentiation antigens of human hemopoietic cells: patterns of reactivity of two monoclonal antibodies.

Two mouse anti-human monoclonal antibodies (S3.13 and S5.7) raised against cells of acute myelogenous leukemia were found to react with antigens expressed on the surface of subsets of monocytes and lymphocytes. S3.13 precipitates a peptide of Mr 29,000, and S5.7 precipitates a peptide of Mr 20,000 present on the surface of all the cell types tested. These two surface antigens were distributed on discrete subpopulations of normal hemopoietic cells. The antibodies reacted with all (S5.7) or a subpopulation (S3.13) of peripheral blood T-lymphocytes, and with a subset of monocytes. Both antibodies reacted with bone marrow blast cell progenitors of the myelomonocytes and erythroid lineage. S5.7 also reacted with non-T-lymphocytes and with cells of the eosinophilic lineage. Both antigens disappeared from the cell surface during normal myeloid and erythroid differentiation. Thus, these monoclonal antibodies define the molecular characteristics and the cellular distribution of two differentiation antigens present on cells of the hemopoietic lineage.