title: Biologic and molecular characterization of the IgG serum blocking factor (SBF-IgG) isolated from sera of patients with EBV-induced infectious mononucleosis.
abstract: Our laboratory has previously reported the isolation of a serum blocking factor (SBF) from infectious mononucleosis (IM) patients. The SBF has been purified by a combination of Sephadex QAE-50 ion exchange and Sephadex G-200 molecular sieve chromatography. This material was found to be devoid of soluble immune complexes, and immunochemically and biochemically was characterized as IgG and, hence, termed SBF-IgG. The SBF-IgG was shown to significantly (alpha = 0.05) suppress antigen specific (Influenza A-1[H1N1]) in vitro lymphocyte stimulation (LS) as well as leukocyte migration-inhibition (LMI) reactivity. Also, the SBF-IgG significantly suppressed the in vitro.LS response to phytohemagglutinin. In addition, the SBF-IgG when bound to normal donor lymphocytes significantly reduced the high affinity E-rosette (HAR) reactivity at 29 degrees C. A purified T lymphocyte subpopulation of normal donor lymphocytes specifically bound SBF-IgG, and the latter could be r covered using glycine-HCI. It appears that SBF-IgG is a nonspecific antibody; it binds neither lymphokines nor specific antigen, but apparently elicits its in vitro vitro cell-mediated suppressive effect at the level of the T lymphocytes.
mesh_terms: D000906:Antibodies / Q000494:pharmacology*; D000936:Antigen-Antibody Complex; D000941:Antigens; D001667:Binding, Competitive; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G; D007244:Infectious Mononucleosis / Q000276:immunology*; D007961:Leukocyte Migration-Inhibitory Factors / Q000378:metabolism; D008222:Lymphokines / Q000378:metabolism; D011487:Protein Conformation; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D000941:Antigens; D007074:Immunoglobulin G; D007961:Leukocyte Migration-Inhibitory Factors; D008222:Lymphokines