Antigens differentially expressed on surface and cytoplasmic structures of human myeloid cells

Specialized internal granules are a major feature of myeloid differentiation and are deficient in most acute myeloid leukemia cells. Although they arise from the same synthetic apparatus as does the plasma membrane, their relationship to it is not well characterized in human tissues. Using murine monoclonal antibodies, we have identified myeloid-related structures that illustrate three possible modes of antigen expression in these organelles. Immunocytochemical studies with the light microscope have shown that the first (D51) was restricted to the surface of neutrophils, monocytes, megakaryocytes and platelets; a second (D46) was found on the surface of blastic cell lines but on only internal components of mature granulocytes; the third (H36/71) appeared on both the surface and internal particles of promyelocytes, myelocytes and polymorphs. These model antigens may be used to study the control of granule synthesis in normal and leukemic cells.