title: Blockade of CTLA-4 enhances allergic sensitization and eosinophilic airway inflammation in genetically predisposed mice.
abstract: CTLA-4 (CD152) expression is restricted to subsets of activated T lymphocytes and shares homology with CD28. CTLA-4 and CD28 molecules both bind to B7 molecules on antigen-presenting cells. Whereas CD28-B7 interaction enhances T cell activation, cytokine production and survival, CTLA-4 signaling down-regulates T cell responses. Here, we studied the involvement of CTLA-4 triggering in the pathogenesis of allergen-induced airway inflammation in mice. Anti-CTLA-4 mAb were injected during i.p. sensitization with ovalbumin (OVA). This treatment favored OVA-specific IgE production and augmented blood eosinophilia in BALB/c mice. In BALB/c mice, enhanced Th2 sensitization after anti-CTLA-4 mAb injections resulted in more severe airway inflammation, and increased airway hyperresponsiveness to metacholine, bronchial eosinophilia and IL-4 and IL-5 levels in broncho-alveolar lavage (BAL) fluid following repeated allergen inhalations. Importantly, aggravation of airway inflammation and enhancement of Th2 responses were accompanied by a significant reduction of pulmonary TGF-beta levels at protein level in BAL fluid as well as on mRNA level in inflamed lung tissue. In contrast to BALB/c mice, blockade of CTLA-4 did not alter IgE production nor the phenotype of airway inflammation or TGF-beta production in C57BL/6 mice. Our data suggest that CTLA-4 triggering represents an important regulatory mechanism for Th2 sensitization in genetically predisposed mice by modulating TGF-beta production.
authors.affiliation: Laboratory of Experimental Immunology, University Hospitals, Faculty of Medicine, U.Z. Gasthuisberg, University of Leuven, Herestraat 49, B-3000 Leuven, Belgium.
authors.forename: Peter W
authors.initials: PW
authors.lastname: Hellings
authors.forename: Peter
authors.initials: P
authors.lastname: Vandenberghe
authors.forename: Ahmad
authors.initials: A
authors.lastname: Kasran
authors.forename: Lieve
authors.initials: L
authors.lastname: Coorevits
authors.forename: Lutgart
authors.initials: L
authors.lastname: Overbergh
authors.forename: Chantal
authors.initials: C
authors.lastname: Mathieu
authors.forename: Jan L
authors.initials: JL
authors.lastname: Ceuppens
mesh_terms: D000069594:Abatacept; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology*; D001249:Asthma / Q000209:etiology / Q000276:immunology; D016535:Bronchial Hyperreactivity / Q000209:etiology* / Q000276:immunology; D060908:CTLA-4 Antigen; D004195:Disease Models, Animal; D004802:Eosinophilia / Q000209:etiology* / Q000276:immunology; D007114:Immunization; D018796:Immunoconjugates; D007073:Immunoglobulin E / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013045:Species Specificity; D013601:T-Lymphocytes / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; D018796:Immunoconjugates; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D007073:Immunoglobulin E; D000069594:Abatacept; D010047:Ovalbumin