Fc receptors for IgE (Fc epsilon R) on human lymphoid cells: inducible expression of Fc epsilon RII (CD23) on lymphocytes and detection by monoclonal anti-Fc epsilon RII antibody.
The studies presented herein describe (1) a sensitive, quantitative, and objective assay for detecting cell membrane-bound form of Fc receptors for IgE displayed on human lymphoid cells based on measuring unlabeled Fc epsilon R-bound IgE by a solid-phase RIA of cell lysate fluids; (2) the development and characterization of an IgM monoclonal antibody, termed 7E4, which is specific for human lymphocyte Fc epsilon RII (CD23) molecules; and (3) a system for reproducibly inducing de novo synthesis and expression of Fc epsilon RII proteins on human lymphocytes following exposure to the mitogenic lectin, pokeweed mitogen. The Fc epsilon RII molecules induced by exposure to PWM were proven to be present on lymphocytes, and not on other cell types in several ways, including (1) documenting sensitivity of such proteins to both acid pH and trypsin treatment, the latter manipulation being ineffective in removing Fc epsilon RII molecules on basophils and mast cells; (2) demonstrating specific reactivity of the expressed Fc epsilon RII molecules with the 7E4 monoclonal antibody, which is specific for human lymphocyte Fc epsilon RII molecules and does not react with Fc epsilon R molecules on other cell types; and (3) observing the required concomitant presence of both T and B lymphocytes during the induction process and proving that the induced Fc epsilon R+ cells are indeed B cells of the Leu-12+ phenotype by fluorescence analysis. The ability to induce expression of Fc epsilon RII molecules on human lymphocytes exposed to a mitogen such as PWM requires special technical attention to the method of preparation and isolation of human lymphoid cells from peripheral blood. This in vitro system for up-regulating Fc epsilon RII expression on human lymphocytes should provide us with an important new tool to analyze the participation of such cells in the regulatory mechanisms controlling the human IgE antibody system.
Ohno
I
I
Division of Immunology, Medical Biology Institute, La Jolla, California 92037.
Hanson
C M
CM
Fitzgerald
P
P
Nonaka
M
M
Katz
D H
DH
D000818:Animals; D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology; D002499:Centrifugation, Density Gradient; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D015847:Interleukin-4; D007378:Interleukins / Q000494:pharmacology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000032:analysis*; D051379:Mice; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011961:Receptors, Fc / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology; D017455:Receptors, IgE; D014357:Trypsin / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte; D007378:Interleukins; D011043:Pokeweed Mitogens; D011961:Receptors, Fc; D017455:Receptors, IgE; D015847:Interleukin-4; D007073:Immunoglobulin E; D014357:Trypsin