Abstract
Asthma is a chronic inflammatory disorder of the airways. In this disease an allergic reaction occurs that shifts T-helper (Th) cells towards a Th2 subtype response to innocuous antigen characterized by a predominant production of the cytokines IL-4, IL-5, IL-9, and IL-13. These cytokines together with mediators from mast cells, basophils and eosinophils lead to IgE class switching, chronic inflammation, massive mucus secretion, and the contraction of smooth muscle cells. However it is unclear how the inflammatory response in the lung is modulated during an allergic reaction. In this study the role of suppressor of cytokine signaling proteins (SaCS) and Th17 cells was examined in the regulation of cytokines, allergic and inflammatory response in the airways.|Most research have used an asthma model with aVA as an antigen and intraperitoneal injections as the route of sensitization, neither being typical of the clinical situation. This study set out to establish a mouse model of asthma closer to clinical situations by using a common antigen, House Dust Mite, and sensitizing the mice intranasally before determining the presence of inflammatory sacs proteins and the novel helper T cell, Th17.|Mice were sensitized either by intranasal administration (IN) or by intraperitoneal injection (IP) with house dust mite antigen. Airway hyperresponsiveness (AHR) was determined by response to methacholine using both non-invasive and invasive methods. H & E staining and Tri-Chrome staining was used to compare morphology and collagen deposition, respectively. Periodic Acid Schiff (PAS) staining was performed to visualize goblet cell hyperplasia and mucus deposition, and immunohistochemistry (IHC) was performed to visualize the expression of sacs 1, 3, and 5.|Intranasal sensitization followed by aerosol challenge with HDM elicited a consistent and significant increase in AHR to methacoline in mice while the IP method was not effective with this antigen. The Thl? cell in asthma was examined and the hematopoietic growth factor FMS-like tyrosine kinase 3 ligand (Flt3L) was used to help determine if the Th17 cell is pro-inflammatory or a regulatory cell in the case of asthma. 5 ~g IP injections of Flt3L were given to mice with established AHR and allergic airway inflammation on ten consecutive days. IHC was performed and the expression of sacs 1, 3 and 5 decreased after treatment with Flt3L. Th17 cells, as indicated by their phenotype of CD4+IL23R+ and mRNA expression of RaR-y, were significantly present in the mice treated with HDM. When treated with Flt3L the number of these cells in the lungs and spleen decreased, suggesting that the Th17 cell is also a contributor to asthma symptoms.