The Th2 lymphocyte products IL-4 and IL-13 rapidly induce airway hyperresponsiveness through direct effects on resident airway cells.
Airway inflammation and airway hyperresponsiveness (AHR) are hallmarks of asthma. Cytokines produced by T helper type 2 (Th2) lymphocytes have been implicated in both processes. There is strong support for the idea that Th2 cytokines can produce AHR indirectly by promoting the recruitment of inflammatory cells. Less attention has been given to the possibility that Th2 cytokines might induce AHR by acting directly on resident airway cells. To investigate this, we polarized and activated CD4(+) T cells in vitro and analyzed airway function after administration of lymphocyte-conditioned media to the airways of naive mice. Th2-lymphocyte-conditioned medium induced AHR within 6 h. This finding was reproduced in mast-cell-deficient and in T- and B-lymphocyte-deficient mice. AHR did not occur when Th2-lymphocyte-conditioned medium was administered to mice lacking the IL-4 receptor alpha subunit or Stat6, suggesting a critical role for interleukin (IL)-4 and/or IL-13. This was confirmed by the finding that recombinant IL-4 and IL-13 both induced AHR within 6 h. The induction of AHR occurred in the absence of inflammatory cell recruitment or mucus production. These results strongly suggest that products of activated Th2 lymphocytes can rapidly perturb airway function through direct effects on resident airway cells.
Venkayya
Rajeev
R
Lung Biology Center, Program in Immunology, University of California San Francisco, Box 0854, San Francisco, CA 94143-0854, USA. rvenk@itsa.ucsf.edu
Lam
Maggie
M
Willkom
Madeleine
M
Grünig
Gabriele
G
Corry
David B
DB
Erle
David J
DJ
D000818:Animals; D001249:Asthma / Q000276:immunology / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000276:immunology / Q000503:physiopathology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D018793:Interleukin-13 / Q000378:metabolism*; D015847:Interleukin-4 / Q000378:metabolism*; D008168:Lung / Q000166:cytology / Q000502:physiology*; D008213:Lymphocyte Activation; D008407:Mast Cells / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D019948:Receptors, Interleukin-4 / Q000235:genetics / Q000378:metabolism; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D050800:STAT6 Transcription Factor; D015398:Signal Transduction / Q000502:physiology; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
D017077:Culture Media, Conditioned; D018398:Homeodomain Proteins; D018793:Interleukin-13; D019948:Receptors, Interleukin-4; D050800:STAT6 Transcription Factor; C494101:STAT6 protein, human; C494100:Stat6 protein, mouse; D015534:Trans-Activators; C064658:RAG-1 protein; D015847:Interleukin-4