title: Mitogenic activation of human lymphocytes: a protein A plaque assay evaluation of polyclonal B-cell activators.
abstract: Using the protein A plaque assay, the capacity of various polyclonal B cell activators to induce differentiation in human B lymphocytes was investigated. Dextran sulphate and native dextran were both virtually devoid of mitogenic properties. Lipopolysaccharide, however, was found to be a potent mitogen in human cells that, although giving rise to low DNA synthetic response, induced high numbers of immunoglobulin-synthesizing cells. Mean plaque-forming cell (PFC) numbers in healthy blood donors assayed on the optimal day (days 5-7) were 23,493 IgM/10(6) cells, 11,288 IgG/10(6) cells, and 2643 IgA/10(6) cells. Values obtained in spleen cells, peaking at days 4-6, were slightly higher. Purified protein derivative (PPD) was equally or even more effective than lipopolysaccharide (LPS) in generating PFC of different subclasses in peripheral blood with mean of 29,241 IgM/10(6), 21,269 IgG/10(6), and 3681 IgA/10(6). PPD furthermore induced a marked DNA synthetic response in human lymphocytes. These data suggest that LPS and PPD may both be used as functional markers in human cells when analysing patients with a suspected immunodeficiency state. It is suggested that cultures should be assayed using the protein A plaque assay, thereby being able not only to investigate the individual immunoglobulin classes but also to avoid the possible hazards involved in measuring antigen-specific responses in patients whose prior immunization to the antigen tested can never be totally excluded.
authors.affiliation: Department of Immunobiology, Karolinska Institute, Wallenberglaboratory, Stockholm, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Hammarström
authors.forename: A G
authors.initials: AG
authors.lastname: Bird
authors.forename: C I
authors.initials: CI
authors.lastname: Smith
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D016264:Dextran Sulfate / Q000494:pharmacology; D003911:Dextrans / Q000494:pharmacology; D006801:Humans; D007158:Immunologic Techniques; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D014373:Tuberculin / Q000494:pharmacology; D010948:Viral Plaque Assay
chemical_list: D003911:Dextrans; D008070:Lipopolysaccharides; D014373:Tuberculin; D004247:DNA; D016264:Dextran Sulfate