Allergen exposure and viral upper respiratory infections are important stimuli which can lead to airway inflammation in asthmatic individuals. Sensitivity to Alternaria, a major aeroallergen, is associated with asthma and can lead to chronic and potentially life-threatening asthma. Viral respiratory infections can precipitate wheezing episodes in asthmatics and enhance the late phase pulmonary response following antigen bronchoprovocation in allergic subjects. Asthma is characterized by inflammation of the airway which involves the interaction of mast cells, T-lymphocytes, and eosinophils. Lymphocytes play a key role in the allergic inflammatory response. Inflammatory cytokines can be generated by virus and allergen stimulated lymphocytes. The mechanism by which virus infection enhances the response to allergen is not known, but may involve the interaction of cytokines generated by virus-specific and allergen- specific T-cells. This study will examine the hypothesis that cytokines secreted by virally activated lymphocytes can affect the generation of certain cytokines (IL-4, lL-5, IFNgamma) produced by Alternaria allergen specific T-lymphocyte clones. Conversely, cytokines produced by allergen specific T-cell clones may affect the production of these cytokines by virally activated lymphocyte clones. Recombinant Alternaria allergens will be produced and Alternaria-specific T-cell clones established. Synthetic peptides based on the amino acid sequence of Alternaria allergens will be used to conduct epitope mapping studies. Cytokine mRNA and protein expression of Alternaria-specific T-cells stimulated by these peptides will be examined. Similarly, rhinovirus 16 (RV16) specific T-cell clones will be established and the cytokine mRNA and protein expression profile determined. Supernatants from Alternaria stimulated T-cell clones will be incubated with RV16 specific T-cells to explore their proliferative response and cytokine mRNA production. Likewise, supernatants from RV16 stimulated T-cells will be incubated with Alternaria-specific T-cells to assess the upregulation of their response. Lastly, supernatants from both Alternaria (presumably lL-5) and RV16-specific T-cell clones (presumably IFNgamma) will be used to assess their effect on eosinophil survival. These studies will permit an in-depth determination of the interaction of allergic and viral-induced reactions at the T-cell level and assess their effect on eosinophil biology which in turn will provide new insight into pathogenesis of asthma.
