title: Involvement of CD28 cosignalling in the T cell-mediated suppression of the IgG antibody response against the TI-2 antigen alpha(1-->3) dextran.
abstract: The humoral immune response against alpha(1-->3) dextran (Dex) in BALB/c mice is characterized by the formation of predominantly IgM antibodies bearing the J558 idiotype. IgG antibodies do not appear in euthymic mice. In athymic animals, however, the response proceeds to a vigorous IgG production. In euthymic mice formation of IgG is suppressed by J558 idiotype specific regulatory T cells recognizing in association with I-Ed and in cognate T/B interaction the V(H) CDR3 derived peptide of the J558 idiotype. Only B-2 lymphocytes produce IgG whereas B-1 cells do not participate in the production of this Ig class. Using novel synthetic all alpha(1-->3)-D-gluco configured tetrasaccharide the Dex-specific B cells can for the first time be analyzed in FACS. In experiments using this newly designed low molecular Dex no signs of B cell apoptosis can be found. This demonstrates a true silencing of persisting Bgamma memory cells as previously suggested by adoptive transfer experiments. In this suppression a further involvement of CD28 and B7-1 interaction can be demonstrated which delivers a necessary costimulatory suppression signal in addition to the cognate TCR/peptide-I-Ed interaction between J558 specific T cells and J558 idiotype bearing B cells.
authors.affiliation: Institute for Immunology, University of Münster, Germany. specht@uni-muenster.de
authors.forename: C
authors.initials: C
authors.lastname: Specht
authors.forename: R
authors.initials: R
authors.lastname: Junker
authors.forename: A
authors.initials: A
authors.lastname: Krüger
authors.forename: A
authors.initials: A
authors.lastname: Rademaekers
authors.forename: H
authors.initials: H
authors.lastname: Redlich
authors.forename: E
authors.initials: E
authors.lastname: Kölsch
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D000955:Antigens, T-Independent / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D018106:CD28 Antigens / Q000276:immunology*; D003911:Dextrans / Q000276:immunology*; D007108:Immune Tolerance / Q000276:immunology*; D007074:Immunoglobulin G / Q000096:biosynthesis*; D051379:Mice; D008807:Mice, Inbred BALB C; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000955:Antigens, T-Independent; D018106:CD28 Antigens; D003911:Dextrans; D007074:Immunoglobulin G; C040834:alpha-1,3-dextran