Date of Award
Doctor of Philosophy (PhD)
Dr. Manel Jordana
Atopic asthma is immunologically-driven condition characterized by reversible bronchoconstriction and Th2-polarized eosinophilic airways inflammation. As such, the development of Th2 responses is a key step in the pathogenesis of the disease. We utilised a murine model of respiratory mucosal sensitization to examine the roles of different cytokines in the generation of polarized immune-inflammatory responses in the airways. Mice were sensitized to ovalbumin (OVA) by daily aerosol exposure in the context of airway expression of GM-CSF, resulting in a Th2-polarized eosinophilic inflammatory response in the airways, reminiscent of asthma; the addition of IL-12 to the airway microenvironment deviated this response toward the Th1 phenotype. We analyzed expression of key Th1-and Th2-associated genes in the lymph nodes during Th1- and Th2-polarized sensitization, and showed that cytokine expression compartmentalized to the respiratory tract can have a profound impact on the nature of developing immune responses in the draining lymph nodes. Next, we investigated the necessity for IL-4 during GM-CSF-driven respiratory mucosal sensitization. We analyzed a variety of Th2-associated factors, including transcription factors, cytokines, chemokine receptors, and cell surface markers, and found that IL-4 was not necessary for Th2-polarization in this model. Finally, we examined whether IL-10 played a rol in mediating Th2 polarization, and observed that mice treated with anti-IL-10 antibodies or genetically deficient in IL-10 showed impaired development of Th2-polarized immune-inflammatory responses. This research highlights the importance of the cytokine microenvironment of the airways in determining the nature of the ensuing immune-inflammatory response, and defines some of the molecular requirements for the polarization of Th responses during respiratory mucosal sensitization in vivo.
Ritz, Stacey, "Cytokine regulation of immune responses in he respiratory mucosa" (2003). Open Access Dissertations and Theses. Paper 1254.