title: Expression and capping of a proliferation-associated surface membrane p34 kDa antigen on different human hematopoietic cell lines.
abstract: A novel surface membrane nonglycosylated acidic polypeptide (34 kDa), encoded by a structural gene on chromosome 11, has been identified using murine monoclonal antibody (MoAb) 53.6 (IgG2a). MoAb 53.6, raised against uninduced cells of a human erythroleukemia line (HEL), recognizes a surface membrane antigen that is displayed on proliferating (cell cycle phase G1, S, and M + G2 phase) human leukocytes. The expression and redistribution (i.e., patching and capping) of the p34 kDa antigen on 27 different long-term human hematopoietic cell (HHC) lines was defined by fluorescence microscopy. These lines had been established from patients with leukemia or healthy donors and included phenotypically defined populations of T cells, B cells, and myelomonocytic cells. Almost all (greater than 95%) of the leukocytes of the 27 lines reacted strongly with MoAb 53.6. The majority of the leukocytes displayed p34 kDa antigen patching (26/27 lines; patched cells, 96-100%); moreover, 20 of 27 lines exhibited p34 kDa antigen capping (capped cells, 8-96%). Presentation of the p34 kDa antigen on surface membrane ultrastructures, imaged with immunogold using an indirect antibody labeling procedure, was illustrated by scanning electron microscopy, and endocytosis of the gold-tagged antigen-antibody complex was studied by transmission electron microscopy. The HHC lines are thought to represent immortalized populations of different human leukocyte subsets that are in different stages of maturation and/or differentiation; thus these lines should prove useful as models for further characterizing this unique p34 kDa proliferation-associated antigen and for defining the mechanisms and significance of surface membrane antigen redistribution and modulation that has been associated with leukocyte activation and propagation.
authors.affiliation: Department of Molecular Immunology, Roswell Park Cancer Institute, Buffalo, New York 14263.
authors.forename: R J
authors.initials: RJ
authors.lastname: Streck
authors.forename: E L
authors.initials: EL
authors.lastname: Hurley
authors.forename: J L
authors.initials: JL
authors.lastname: Pauly
mesh_terms: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis*; D001402:B-Lymphocytes; D002453:Cell Cycle; D002455:Cell Division; D002460:Cell Line; D002462:Cell Membrane / Q000648:ultrastructure; D002880:Chromosomes, Human, Pair 11; D005434:Flow Cytometry; D006410:Hematopoiesis; D006801:Humans; D007938:Leukemia; D007962:Leukocytes / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D013601:T-Lymphocytes
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface