Establishment of a sensitive radioimmunoassay for the detection of human IgE-binding factor (soluble CD23).
A monoclonal antibody (mAb) specific to low-affinity receptor for IgE (FceRII/CD23) was established by the fusion of spleen cells of BALB/c mice immunized with the FceRII+ human B lymphoblastoid cell line (RPMI 8866) with mouse myeloma P3U1. Four mAbs, 10/3 (IgG1), 11/4 (IgG1), 12/2 (IgG2b) and 15/6 (IgM), almost completely inhibited the IgE binding to FceRII+ cells but not to FceRII- cells. More directly, they were demonstrated to react only with 43-kD component/FceRII of the cell lysate of RPMI 8866 cells by sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot analysis. Since they have a different epitope specificity, a solid-phase radioimmunoassay (RIA) for the measurement of IgE-binding factor (IgE-BF) was established. It was found that the RIA with the use of 10/3 and 125I-labeled 11/4 or 12/2 gave good results in the detection of IgE-BF derived from B cells and monocytes as well as of T-cell-derived IgE-BF. More importantly, serum IgE-BF was also quantitatively measured by this RIA. Although increased serum levels of IgE-BF were observed in atopic patients, serum IgE-BF was decreased rather than increased in patients with very high serum IgE. This phenomenon may be explained by the decreased ability of the patients' B cells to spontaneously release IgE-BF in vitro.
Yanagihara
Y
Y
Clinical Research Center for Allergy, National Sagamihara Hospital, Kanagawa, Japan.
Kiniwa
M
M
Kajiwara
K
K
Shida
T
T
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D000939:Epitopes / Q000032:analysis; D006801:Humans; D015847:Interleukin-4 / Q000494:pharmacology; D008222:Lymphokines / Q000032:analysis* / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D029584:Prostatic Secretory Proteins; D011863:Radioimmunoassay; D017455:Receptors, IgE / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D000911:Antibodies, Monoclonal; D000939:Epitopes; D008222:Lymphokines; D029584:Prostatic Secretory Proteins; D017455:Receptors, IgE; C043076:beta-microseminoprotein; C013059:immunoglobulin-binding factors; D015847:Interleukin-4