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Background: Adoptive transfer of helper T (Th) cells conferred a late asthmatic response upon antigen challenge. A possible production of a contractile activity for bronchial smooth muscle (BSM) by activated Th cells was examined. Method: Murine Th clones were stimulated with immobilized anti-CD3 antibody in the presence or absence of anti-CD28 antibody. Culture supernatants were dialyzed and then applied to the collagen gels containing cultured human BSM cells. Results: Culture supernatants of activated but not resting murine Th clones that conferred a late asthmatic response, induced the contraction of human BSM cell-containing collagen gels. Conclusion: Activated Th cells produce a contractile activity for BSM in vitro. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Glucocorticoid (GC) action on asthma has been partly explained by the inhibition of T cell activation. We analyzed the steroid sensitivity of ovalbumin (OVA) reactive helper T (Th) cell clones both in vitro and in vivo. Method: For in vitro experiments, Th clones were cultured with antigen-presenting cells, OVA, and various concentrations of dexamethasone (DEX). The proliferative response of each Th clone was measured by 3H-thymidine uptake. For in vivo experiments, unprimed BALB/c mice were transferred with Th clones, challenged with OVA, and administered DEX subcutaneously. The number of infiltrating cells in bronchoalveolar lavage fluid (BALF) was measured. Results: Six Th clones were classified as steroid-sensitive or steroid-resistant clones in terms of the effects of GC on the proliferative responses analyzedin vitro. Airway infiltration of eosinophils and lymphocytes of mice transferred with steroid-sensitive clones were effectively inhibited by the administration of DEX. In contrast, those of mice transferred with steroid-resistant clones were not significantly inhibited by DEX; the number of eosinophils in the BALF of mice transferred with 1 steroid-resistant clone, i.e. T5-1, was only partially reduced. Conclusion: The steroid sensitivity of Th clones measured in vitro was consistent with that of an adoptively transferred asthma model measuredin vivo. Steroid-sensitive and resistant asthma models seem valuable for understanding the mechanisms of steroid resistance in severe asthma. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Helper T (Th) cells are deeply involved in the pathophysiology of bronchial asthma, such as eosinophilic inflammation, bronchial hyperresponsiveness (BHR), airflow limitation and remodeling. It is still unclear whether Th cells contribute to BHR independently of eosinophilic inflammation. The double GATA (dblGATA) site is a high-affinity GATA-binding site in the GATA-1 promoter. dblGATA site-deficient (ΔdblGATA) mice lack eosinophils. Method: Ovalbumin (OVA)-reactive Th clones were transferred into ΔdblGATA and wild-type (WT) mice of BALB/c background. The number of eosinophils in the bronchoalveolar lavage fluid (BALF) and bronchial responsiveness to methacholine were examined after OVA challenge. Results: The number of BALF eosinophils was significantly increased in WT mice, but not detectable in ΔdblGATA mice. BHR was also induced in WT mice, but significantly attenuated in ΔdblGATA mice. Conclusion: Eosinophils are involved in T-cell-mediated BHR. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]