title: B cells play key roles in th2-type airway immune responses in mice exposed to natural airborne allergens.
abstract: Humans are frequently exposed to various airborne allergens. In addition to producing antibodies, B cells participate in immune responses via various mechanisms. The roles of B cells in allergic airway inflammation and asthma have been controversial. We examined the functional importance of B cells in a mouse model of asthma, in which mice were exposed repeatedly to common airborne allergens. Naïve wild-type BALB/c mice or B cell-deficient JH-/- mice were exposed intranasally to a cocktail of allergen extracts, including Alternaria, Aspergillus, and house dust mite, every other day for two weeks. Ovalbumin was included in the cocktail to monitor the T cell immune response. Airway inflammation, lung pathology, and airway reactivity were analyzed. The airway exposure of naïve wild type mice to airborne allergens induced robust eosinophilic airway inflammation, increased the levels of Th2 cytokines and chemokines in the lung, and increased the reactivity to inhaled methacholine. These pathological changes and immune responses were attenuated in B cell-deficient JH-/- mice. The allergen-induced expansion of CD4+ T cells was impaired in the lungs and draining lymph nodes of JH-/- mice. Furthermore, lymphocytes from JH-/- mice failed to produce Th2 cytokines in response to ovalbumin re-stimulation in vitro. Our results suggest that B cells are required for the optimal development of Th2-type immune responses and airway inflammation when exposed to common airborne allergens. The therapeutic targeting of B cells may be beneficial to treat asthma in certain patients.
authors: Department of Internal Medicine, Division of Allergic Diseases, Mayo Clinic, Rochester, Minnesota, United States of America.
authors: Li Yin
authors: LY
authors: Drake
authors: Department of Internal Medicine, Division of Allergic Diseases, Mayo Clinic, Rochester, Minnesota, United States of America.
authors: Koji
authors: K
authors: Iijima
authors: Department of Internal Medicine, Division of Allergic Diseases, Mayo Clinic, Rochester, Minnesota, United States of America.
authors: Kenichiro
authors: K
authors: Hara
authors: Department of Internal Medicine, Division of Allergic Diseases, Mayo Clinic, Rochester, Minnesota, United States of America.
authors: Takao
authors: T
authors: Kobayashi
authors: Department of Internal Medicine, Division of Allergic Diseases, Mayo Clinic, Rochester, Minnesota, United States of America.
authors: Gail M
authors: GM
authors: Kephart
authors: Department of Internal Medicine, Division of Allergic Diseases, Mayo Clinic, Rochester, Minnesota, United States of America; Department of Immunology, Mayo Clinic, Rochester, Minnesota, United States of America.
authors: Hirohito
authors: H
authors: Kita
mesh_terms: D000388:Air; D000391:Air Microbiology; D000485:Allergens / Q000276:immunology*; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D002452:Cell Count; D002454:Cell Differentiation / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D006801:Humans; D008168:Lung / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D039981:Pyroglyphidae / Q000276:immunology; D012137:Respiratory System / Q000276:immunology* / Q000382:microbiology; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
chemical_list: D000485:Allergens; D016207:Cytokines