title: Identification of an immunodominant T cell epitope on cholera toxin.
abstract: Cholera toxin (CT), the enterotoxin of Vibrio cholerae, is a potent mucosal immunogen as well as a strong mucosal adjuvant to related and unrelated antigens. The mucosal immune response to CT is T cell dependent and MHC class II restricted. The epitopes on CT recognized by T cells have not been identified. The purpose of this study was to determine the fine specificity of T cell recognition of both the CT A subunit (CT-A) and the CT B subunit (CT-B) by using a range of synthetic peptides. After immunization with CT-B or CT-A in CFA subcutaneously, the peripheral lymph node T cells were stimulated with different synthetic peptides in vitro. The peptide specificity of T cell recognition was identified by assaying T cell proliferation and interleukin-3 production. T cells from C57BL/6 (H-2b) high responder mice recognized one immunodominant epitope (peptide 89-100) and one weak epitope (peptide 31-50) on CT-B and two epitopes (peptide 21-39 and 180-194) on CT-A. The immunization of C57BL/6 mice with synthetic immunodominant CT-B peptide 89-100 induced T cell immunity to the pentameric CT-B. Induction of tolerance to CTB peptide 89-100 by i.v. injection in high responder C57BL/6 mice induced unresponsiveness to mucosal immunization with CT, compatible with an immunodominant role for this T cell epitope.
authors.affiliation: Division of Gastroenterology and Hepatology, University of Alabama at Birmingham 35294-0007, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Cong
authors.forename: H R
authors.initials: HR
authors.lastname: Bowdon
authors.forename: C O
authors.initials: CO
authors.lastname: Elson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002772:Cholera Toxin / Q000138:chemical synthesis / Q000276:immunology*; D005260:Female; D006183:H-2 Antigens / Q000235:genetics; D007108:Immune Tolerance / Q000276:immunology; D016056:Immunodominant Epitopes / Q000032:analysis*; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D006183:H-2 Antigens; D016056:Immunodominant Epitopes; D002772:Cholera Toxin