title: Preparation and characterization of monoclonal antibodies recognizing two distinct differentiation antigens (Pro-Im1, Pro-Im2) on early hematopoietic cells.
abstract: A series of monoclonal antibodies recognizing myeloid differentiation antigens were prepared by immunizing Balb/c mice with HL-60 cells. Hybrids secreting antibodies reactive with HL-60 cells but unreactive with peripheral blood mononuclear cells were isolated and further cloned. One clone was found to produce an IgG2a antibody recognizing an 85,000-dalton molecular weight surface glycoprotein, and a second clone was found to produce an IgM antibody recognizing a heat-stable determinant present on a glycolipid. We have termed these antigens Pro-Im1 and Pro-Im2, respectively (Pro for using HL-60 promyelocytes as an immunogen and Im for the presence of these antigens on immature cells). alpha Pro-Im1 and alpha Pro-Im2 were used to investigate the surface expression and tissue distribution of these two antigens. Pro-Im1 and Pro-Im2 were found to be brightly expressed on a fraction of fetal liver hematopoietic and bone marrow cells. Both antibodies mediated complement-dependent inhibition of CFU-GM, BFU-E, and CFU-GEMM formation assayed by soft agar colony and burst formation, indicating the expression of these antigens by early hematopoietic precursor cells. This was further confirmed by the induction of HL-60 cells by TPA to differentiate into more mature monocytes and macrophages, accompanied by the loss of both antigens. Pro-Im1 and Pro-Im2 were absent from peripheral blood monocytes, erythrocytes, and platelets, but Pro-Im2 was expressed on granulocytes. Both antigens were absent from thymocytes and peripheral T cells. Cytofluorographic analysis suggested their absence from peripheral blood B cells but that both were expressed on a minority of tissue B cells. Analysis of 150 cases of various myeloid and lymphoid malignancies demonstrated Pro-Im1 and Pro-Im2 expression on myeloblasts and promyelocytes from some acute myelogenous leukemias as well as some B cell malignancies, suggesting that these antigens are shared by early hematopoietic cells and a subset of B cells.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000302:isolation & purification; D000951:Antigens, Neoplasm / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002460:Cell Line; D003114:Colony-Forming Units Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006801:Humans; D007945:Leukemia, Lymphoid / Q000097:blood; D015470:Leukemia, Myeloid, Acute / Q000097:blood; D008099:Liver / Q000166:cytology; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D010703:Phorbol Esters
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D010703:Phorbol Esters