title: A monoclonal antibody reactive with human peripheral blood monocytes.
abstract: A monoclonal antibody directed at a determinant on human peripheral blood monocytes was produced and characterized. This hybridoma antibody, termed OKM1, was reactive by indirect immunofluorescence and complement- (C) mediated lysis with adherent mononuclear cells. OKM1 was unreactive with lymphocytes, thymocytes, lymphoblastoid cell lines, and tumor cells of the T or B cell lineage. In contrast, acute myelomonocytic leukemia cells and granulocytes were reactive with the antibody. Pretreatment of peripheral blood mononuclear cells with OKM1 and C before culture with soluble antigens totally abolished their antigen-induced proliferative response. This function was restored by addition of 1% adherent cells. These findings provided additional support for the notion that OKM1 was reactive with monocytes. In addition, OKM1 appeared to define two distinct populations of monocytes; an adherent population of large cells bearing surface Ia determinants and a nonadherent population of small, Ia-negative cells. These OKM1+ Ia- cells were found to be a contaminant of most fractionated mononuclear cell subsets including the E-SIg-Null cell population.
mesh_terms: D000818:Animals; D000906:Antibodies; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000276:immunology; D002448:Cell Adhesion; D002455:Cell Division; D002999:Clone Cells / Q000276:immunology; D003165:Complement System Proteins; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D051379:Mice; D009000:Monocytes / Q000166:cytology / Q000276:immunology*; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000906:Antibodies; D003165:Complement System Proteins