title: CD81 on B cells promotes interleukin 4 secretion and antibody production during T helper type 2 immune responses.
abstract: Mice lacking CD81 (TAPA-1), a widely expressed tetraspanin molecule, have impaired antibody responses to protein antigens. This defect is specific to antigens that preferentially stimulate a T helper 2 response (ovalbumin or keyhole limpet hemocyanin in alum) and is only seen with T cell-dependent antigens. Absence of CD81 on B cells is sufficient to cause the defect. Also, antigen-specific interleukin (IL) 4 production is greatly reduced in the spleen and lymph nodes of CD81-null mice compared with heterozygous littermates. Thus, expression of CD81 on B cells is critical for inducing optimal IL-4 and antibody production during T helper 2 responses. These findings suggest that CD81 may interact with a ligand on T cells to signal IL-4 production. By using a soluble form of CD81 as a probe, a putative ligand for CD81 was identified on a subset of B and T cells. Two possible models for the interaction of CD81 on B cells with a potential ligand on either B or T cells are proposed.
authors.affiliation: Department of Medicine/Oncology, Stanford University Medical Center, Stanford, CA 94305, USA. hmaecker@cmgm.stanford.edu
authors.forename: H T
authors.initials: HT
authors.lastname: Maecker
authors.forename: M S
authors.initials: MS
authors.lastname: Do
authors.forename: S
authors.initials: S
authors.lastname: Levy
mesh_terms: D000818:Animals; D000917:Antibody Formation; D015703:Antigens, CD / Q000235:genetics* / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology*; D002678:Chimera; D004797:Enzyme-Linked Immunosorbent Assay; D006433:Hemocyanins / Q000276:immunology; D006579:Heterozygote; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000097:blood; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis* / Q000378:metabolism; D008198:Lymph Nodes / Q000276:immunology; D008565:Membrane Proteins / Q000172:deficiency / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D018448:Models, Immunological; D010047:Ovalbumin / Q000276:immunology; D013154:Spleen / Q000276:immunology; D060225:Tetraspanin 28; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D015703:Antigens, CD; C554799:Cd81 protein, mouse; D007074:Immunoglobulin G; D008565:Membrane Proteins; D060225:Tetraspanin 28; D015847:Interleukin-4; D007371:Interferon-gamma; D010047:Ovalbumin; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin