That rhinovirus (RV) infection is commonly associated with asthma exacerbations is well recognized, but the mechanisms responsible for the association are not known. We hypothesize that changes in gene expression, especially of genes for mediators related to the immune response, play a major role in symptom pathogenesis. The respiratory epithelial cells is the host cell for RV replication, but there is currently little information about changes in airway epithelial gene expression caused by RV infection. The goal of this proposal is to define changes in airway epithelial cell gene expression caused by RV infection. The goal of this proposal is to define a subset of genes, derived from gene expression profiles, that are associated with RV-induced airway inflammation and asthma exacerbations. To achieve this goal, our first aim is to elucidate differentially inflammation and asthma exacerbations. To achieve this goal, our first aim is to elucidate differentially expressed genes associated with RV infection of primary cultures of human airway epithelial cells as well as cell expressed genes associated with RV infection of primary cultures of human airway epithelial cells as well as cell lines. In pursuing this aim, we will test the hypothesis that RV infection alters that pattern of gene expression. We plan also to examine whether these changes are influenced by host cell types, viral serotypes, and differently passaged strains on the same serotype. We will carry out gene expression profiling on array membranes that contain 45,000 sequence-verified unit-EST cDNAs or on a 30,000 cDNA cloned library derived from a well-differentiated culture of human airway epithelial cells. In Aim 2 we will profile the expression pattern of differentiated culture of human airway epithelial cells. In Aim 2 we will profile the expression pattern of differentiated culture of human airway epithelial cells. In Aim 2 we will profile the expression patter of selected genes with cytokine production in airway epithelial cells after RV infection. We will test the selected genes associated with cytokine production in airway epithelial cells after RV infection. We will test the hypothesis that a subset of gene expression profiles is involved in the regulation of cytokine induction in these RV-infected cells. To test the hypothesis, gene clustering and profiling pattern of these selected gene sets need to be established and their relation to RV-induced cytokine production needs to be determined. In Aim 3 we will elucidate the functional roles of some of these selected genes in the regulation of cytokine gene expression. We will test the hypothesis that some of these genes are involved in the activation of NF-kappaB system. We will determine how RV activates the NF-kappaB system and will examine whether it is the molecular mechanism underlying the variation in cytokine gene expression in various situations. This project will use viral isolates from Core B. It will interact closely with Project 1 regarding epithelial structure and function after various infections in vitro, and with Project 2 regarding the clinical outcome of infections in vivo. The significance of selected gene expression in clinical situation will be further quantified by Core C.