The H1 histamine receptor regulates allergic lung responses

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Abstract

Histamine, signaling via the type 1 receptor (H1R), has been shown to suppress Th2 cytokine production by in vitro cultured T cells. We examined the role of H1R in allergic inflammation in vivo using a murine asthma model. Allergen-stimulated splenic T cells from sensitized H1R–/– mice exhibited enhanced Th2 cytokine production. Despite this Th2 bias, allergen-challenged H1R–/– mice exhibited diminished lung Th2 cytokine mRNA levels, airway inflammation, goblet cell metaplasia, and airway hyperresponsiveness (AHR). Restoration of pulmonary Th2 cytokines in H1R–/– mice by intranasal IL-4 or IL-13 restored inflammatory lung responses and AHR. Further investigation revealed that histamine acts as a T cell chemotactic factor and defective T cell trafficking was responsible for the absence of lung inflammation. Cultured T cells migrated in response to histamine in vitro, but this was ablated by blockade of H1R but not H2R. In vivo, allergen-specific WT but not H1R–/– CD4+ T cells were recruited to the lungs of naive recipients following inhaled allergen challenge. H1R–/– T cells failed to confer airway inflammation or AHR observed after transfer of WT T cells. Our data establish a role for histamine and H1R in promoting the migration of Th2 cells into sites of allergen exposure.

Authors

Paul J. Bryce, Clinton B. Mathias, Krista L. Harrison, Takeshi Watanabe, Raif S. Geha, Hans C. Oettgen