title: Blockade of T cell costimulation by CTLA4-Ig inhibits lung inflammation in murine hypersensitivity pneumonitis.
abstract: Hypersensitivity pneumonitis (HP) is characterized by an influx of activated T cells in the lungs. The CD28/B7 system provides costimulatory signals essential for complete T cell activation and differentiation. We have previously demonstrated that alveolar macrophages from patients with HP have an up-regulated expression of B7 molecules. In the present study, we investigated the effect of i. p. administration of CTLA4-Ig, a CD28/B7 antagonist, on the lung inflammation of mice inoculated with Saccharoplyspora rectivirgula (SR), a major causative agent of HP. Five groups of C57BL/6 mice were intranasally instilled with SR or saline for 3 consecutive days per wk during 3 wk. CTLA4-Ig was administered starting either after 1 wk of SR challenge or 6 h before the first antigenic exposure and continued during the whole period of sensitization. A control-IgG was given similarly during the 3 wk of SR exposure. The groups included: 1, saline; 2, SR; 3, SR + control-Ig; 4, SR + CTLA4-Ig for the last 2 wk; and 5, SR + CTLA4-Ig for 3 wk. CTLA4-Ig treatment markedly decreased lung inflammation as shown by significantly fewer inflammatory cells in the bronchoalveolar lavage and in lung tissue and reduced SR-specific serum and bronchoalveolar lavage Ig levels. Production of IL-4, IL-10, and IFN-gamma by IL-2-stimulated pulmonary T cells was also decreased by CTLA4-Ig. Administration of CTLA4-Ig did not affect the SR-induced up-regulation of B7-2 expression. These results show that blockade of CD28/B7 interactions by CTLA4-Ig inhibits SR-induced lung inflammation and immune response to SR Ag in mice and may provide a novel approach in the treatment of HP.
authors.affiliation: Unité de Recherche, Centre de Pneumologie, Hôpital Laval, Université Laval, Ste Foy, Quebec, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Israël-Assayag
authors.forename: M
authors.initials: M
authors.lastname: Fournier
authors.forename: Y
authors.initials: Y
authors.lastname: Cormier
mesh_terms: D000069594:Abatacept; D000542:Alveolitis, Extrinsic Allergic / Q000276:immunology / Q000473:pathology* / Q000517:prevention & control*; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D015703:Antigens, CD / Q000096:biosynthesis; D000943:Antigens, Differentiation / Q000008:administration & dosage / Q000494:pharmacology*; D018122:B7-1 Antigen / Q000096:biosynthesis; D051940:B7-2 Antigen; D060908:CTLA-4 Antigen; D002465:Cell Movement / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D018796:Immunoconjugates; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D008168:Lung / Q000276:immunology / Q000473:pathology*; D008213:Lymphocyte Activation / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial; D015703:Antigens, CD; D000943:Antigens, Differentiation; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D060908:CTLA-4 Antigen; C497965:Cd86 protein, mouse; C556707:Ctla4 protein, mouse; D016207:Cytokines; D018796:Immunoconjugates; D007166:Immunosuppressive Agents; D008562:Membrane Glycoproteins; D000069594:Abatacept