Molecular analysis of membrane gamma 2b heavy chain expression.
In order to study T cell regulation of B cell isotype differentiation we have developed a model system consisting of clonal populations of T and B cells. Using this system we have shown that the murine B cell lymphoma, 70Z/3, can be induced to express membrane IgG2b by exposure to a T cell hybridoma derived from the Peyer's patch (termed HAJ-3). The membrane bound IgG2b (mIgG2b) expression is associated with induction of gamma 2b-mRNA, but switch region rearrangement and C mu deletion does not occur. While LPS-stimulated 70Z/3 B cells also express considerable amounts of gamma 2b-mRNA they do not express detectable mIgG2b, indicating that T cell influence is necessary for the production of translatable gamma 2b-specific mRNA. Both the LPS and T cell induced gamma 2b mRNA transcripts lack VH sequences, implying that the surface IgG2b detected lacks a variable region. These findings lend support to a two step model of B cell isotype switching and provide evidence that T cells can regulate early events involved in B cell isotype differentiation.
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002469:Cell Separation; D002872:Chromosome Deletion; D005434:Flow Cytometry; D006825:Hybridomas / Q000276:immunology; D007127:Immunoglobulin Constant Regions / Q000276:immunology; D007074:Immunoglobulin G / Q000096:biosynthesis; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis*; D007142:Immunoglobulin gamma-Chains / Q000096:biosynthesis*; D051379:Mice; D008815:Mice, Inbred Strains; D012150:Polymorphism, Restriction Fragment Length; D012333:RNA, Messenger / Q000096:biosynthesis; D011947:Receptors, Antigen, B-Cell / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology*; D014407:Tumor Cells, Cultured / Q000276:immunology
D007127:Immunoglobulin Constant Regions; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D007142:Immunoglobulin gamma-Chains; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell