title: The regulatory effect of histamine on the immune response: III. Defect on in vitro IgE production in atopics.
abstract: Spontaneous in vitro production of IgE was found higher in a group of untreated grass sensitive atopic patients than in normal volunteers when assessed at the cellular level with a reverse hemolytic plaque assay. This study also confirmed the increase of IgE synthesis after pokeweed mitogen stimulation in non-atopic donors and its decrease in atopic patients. Moreover, in this work we looked for a potential defect in immunoregulatory functions in atopic patients toward the in vitro IgE production. Indeed, histamine is known to activate suppressor cells capable, in turn, of suppressing IgG and IgE production from normal cells. In atopic patients, histamine could activate cells capable of suppressing IgG production but not IgE. Furthermore, similar findings were found when Concanavalin A-induced suppressor cells were examined. These findings suggest (a) a defective regulatory function towards IgE in atopic patients and (b) that the same subpopulation of suppressor cells seems to be activated by histamine and ConA and defective in atopic patients.
mesh_terms: D000921:Antibody-Producing Cells / Q000378:metabolism; D001402:B-Lymphocytes / Q000378:metabolism; D003208:Concanavalin A / Q000494:pharmacology; D006462:Hemolytic Plaque Technique; D006632:Histamine / Q000494:pharmacology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology*; D007073:Immunoglobulin E / Q000096:biosynthesis*; D007074:Immunoglobulin G / Q000096:biosynthesis; D011043:Pokeweed Mitogens / Q000494:pharmacology; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D011043:Pokeweed Mitogens; D003208:Concanavalin A; D007073:Immunoglobulin E; D006632:Histamine