title: 4-1 BB stimulation inhibits allergen-specific immunoglobulin E production and airway hyper-reactivity but partially suppresses bronchial eosinophilic inflammation in a mouse asthma model.
abstract: BACKGROUND
  4-1 BB, a member of the tumour necrosis factor receptor superfamily, functions as a co-stimulatory molecule. Recently, stimulation of the 4-1 BB pathway was shown to suppress antigen-specific CD4(+) T cell and subsequent T cell-dependent humoral immune responses.
  
  
  OBJECTIVE
  We examined the effect of agonistic anti-4-1 BB monoclonal antibody (mAb) treatment on allergic asthma, in which allergen-specific type 2 helper T cells (Th2) have been shown to play an important role.
  
  
  METHODS
  BALB/c mice were systemically sensitized with intraperitoneal injections of ovalbumin (OVA) and alum on days 0 and 14, and then challenged with inhaled OVA on days 28, 29 and 30. In test groups, the agonistic anti-4-1 BB mAb was administered at the time of initial systemic sensitization with OVA. On day 31, mice were challenged with inhaled methacholine, and enhanced pause was measured as an index of airway hyper-responsiveness (AHR). Levels of OVA-specific IgE in serum, and levels of various cytokines in bronchoalveolar lavage (BAL) fluids were measured. The severity of airway inflammation was determined by differential cell counts in BAL fluids and histopathologic lung analysis. To evaluate local immunity, we cultured lymphocytes from draining perihilar lymph nodes and evaluated the proliferative response to OVA and the levels of IL-5 in the culture supernatant. In addition, the functional mechanism of 4-1 BB stimulation was evaluated in splenocytes obtained at day 7 after systemic OVA sensitization.
  
  
  RESULTS
  We found that treatment with the anti-4-1 BB mAb significantly decreased AHR and the production of allergen-specific IgE. Bronchial inflammation, however, had only partially improved and the levels of IL-4 and IL-5 in BAL fluids showed only a small degree of reduction compared with the control Ig-treated mice. Thoracic lymphocytes from anti-4-1 BB-treated mice showed significant suppression of OVA-induced proliferation and IL-5 production. In anti-4-1 BB-treated mice, splenocytes exhibited poor proliferation and marked apoptosis 7 days after systemic OVA challenge.
  
  
  CONCLUSIONS
  These results suggest that stimulation of the 4-1 BB pathway effectively suppresses some features of allergic asthma, including allergen-specific IgE production and AHR, through deletion of allergen-specific Th2 cells. However, we found that bronchial allergic inflammation was not strictly mediated by suppression of the Th2 immune response in this murine model of asthma. Despite these somewhat contradictory effects, intervention in the 4-1 BB pathway might provide a potential novel immunotherapeutic approach for treatment of allergic asthma.
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Cho
authors.forename: B
authors.initials: B
authors.lastname: Kwon
authors.forename: T-H
authors.initials: TH
authors.lastname: Lee
authors.forename: T-B
authors.initials: TB
authors.lastname: Kim
authors.forename: K-A
authors.initials: KA
authors.lastname: Moon
authors.forename: S
authors.initials: S
authors.lastname: La
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: S D
authors.initials: SD
authors.lastname: Lee
authors.forename: Y-M
authors.initials: YM
authors.lastname: Oh
authors.forename: H-B
authors.initials: HB
authors.lastname: Moon
mesh_terms: D000485:Allergens / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D015703:Antigens, CD / Q000276:immunology*; D017209:Apoptosis / Q000276:immunology; D001249:Asthma / Q000276:immunology / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D016535:Bronchial Hyperreactivity / Q000276:immunology / Q000473:pathology / Q000517:prevention & control; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004802:Eosinophilia / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D005260:Female; D007073:Immunoglobulin E / Q000096:biosynthesis* / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D018655:Lymphocyte Count; D051379:Mice; D008807:Mice, Inbred BALB C; D017475:Receptors, Nerve Growth Factor / Q000276:immunology*; D018124:Receptors, Tumor Necrosis Factor / Q000276:immunology*; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9
chemical_list: D000485:Allergens; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D016207:Cytokines; D007074:Immunoglobulin G; D017475:Receptors, Nerve Growth Factor; D018124:Receptors, Tumor Necrosis Factor; C505715:Tnfrsf9 protein, mouse; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9; D007073:Immunoglobulin E