title: Spontaneous IgM autoantibody production in vitro by B lymphocytes of normal human neonates.
abstract: Human neonate B lymphocytes display unique phenotypic and functional characteristics: in addition to CD1c antigens, CD5+ and CD5- subsets both express activation markers such as CD23 and Bac-1. They proliferate strongly in the presence of various lymphokines (rIL-2, rIL-4, low molecular weight BCGF), but differentiate poorly in the presence of the same lymphokines, pokeweed mitogen and Epstein-Barr virus. It has also been reported that human neonate B lymphocytes produce polyreactive autoantibodies after in vitro activation by Staphylococcus aureus Cowan I and transformation by Epstein-Barr virus. We now show that, in the absence of in vitro stimulation, human neonate B lymphocytes produce polyreactive antibodies of the IgM isotype against several autoantigens. The B lymphocytes involved expressed membrane IgD, IgM, CD23 and CD11b molecules; CD5 expression was variable. This phenotype was consistently found on a minority of B lymphocytes and is similar to that of polyreactive autoantibody-producing B cells in mice. We also found that autoantibody production in vitro could occur in the absence of any T helper effect. The function of these autoantibodies is not clearly established, but their occurrence in a large proportion of human neonates strongly suggests that they play an important role in the development of the immune system.
authors.affiliation: Unité d'Immunocytochimie, URA359 CNRS, Institut Pasteur, Paris, France.
authors.forename: R
authors.initials: R
authors.lastname: Barbouche
authors.forename: M
authors.initials: M
authors.lastname: Forveille
authors.forename: A
authors.initials: A
authors.lastname: Fischer
authors.forename: S
authors.initials: S
authors.lastname: Avrameas
authors.forename: A
authors.initials: A
authors.lastname: Durandy
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology; D001323:Autoantibodies / Q000096:biosynthesis*; D001324:Autoantigens / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D018956:CD5 Antigens; D002478:Cells, Cultured; D005312:Fetal Blood / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007132:Immunoglobulin Isotypes / Q000276:immunology; D007075:Immunoglobulin M / Q000096:biosynthesis*; D016130:Immunophenotyping; D007231:Infant, Newborn; D016177:Macrophage-1 Antigen / Q000276:immunology; D011961:Receptors, Fc / Q000276:immunology; D017455:Receptors, IgE; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D001323:Autoantibodies; D001324:Autoantigens; D018956:CD5 Antigens; D007132:Immunoglobulin Isotypes; D007075:Immunoglobulin M; D016177:Macrophage-1 Antigen; D011961:Receptors, Fc; D017455:Receptors, IgE; D007073:Immunoglobulin E