Fine specificity of a rabbit antibody interacting with human IgG Fc receptor-like molecules.
A polyclonal rabbit antibody raised against an Fc receptor (FcR)-like membrane glycoprotein fraction of chronic leukaemic lymphocytes has previously been prepared and partially characterized. This antibody, called AbA, was found to precipitate a 70-kDa and a 45-kDa fraction of the detergent lysate of U937 cells and to inhibit ligand binding to Fc gamma R on the P388D1 murine macrophage cell line. In the present work we have characterised this antibody further. All Fc gamma RII-positive B lymphoblastoid cell lines, as well as resting human B lymphocytes, were positively stained with the AbA antibody. U937 cells were found to be negative, but after stimulation with phorbol ester (PMA), 50% of the cells became positive. AbA antibody did not react with human T cell lines or with the T + 0 cell subset of peripheral blood. Monocytes were also negative. On the other hand, AbA antibody exhibited a dose-dependent inhibition of antibody-mediated cytotoxic reaction (ADCC) of monocytes, while not affecting K cell-mediated ADCC. It had an inhibitory effect of EA rosette formation of B cells and stimulated U937 cells. Furthermore, it interacted with the soluble form of Fc gamma RII released by activated B lymphocytes, and--similarly to IgG--precipitated a 33 kDa fraction from the supernatant of B cells.
Rozsnyay
Z
Z
Dept. of Immunology, L. Eötvös University, Göd, Hungary.
Sármay
G
G
Szabó
I
I
Medgyesi
G
G
Gorini
G
G
Gergely
J
J
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000912:Antibodies, Neoplasm / Q000276:immunology; D000920:Antibody-Dependent Cell Cytotoxicity; D000943:Antigens, Differentiation / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000276:immunology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000473:pathology; D008562:Membrane Glycoproteins / Q000276:immunology*; D009363:Neoplasm Proteins / Q000276:immunology; D011817:Rabbits; D011961:Receptors, Fc / Q000276:immunology*; D017452:Receptors, IgG; D014407:Tumor Cells, Cultured / Q000276:immunology
D000906:Antibodies; D000912:Antibodies, Neoplasm; D000943:Antigens, Differentiation; D000951:Antigens, Neoplasm; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D011961:Receptors, Fc; D017452:Receptors, IgG