The overall goal of this program is to explore whether intradermal (i.e.) gene vaccination is a potential modality for the therapy of allergic diseases. We will investigate the molecular mechanisms by which allergen gene vaccination initiates the Th1 response and evaluate the cellular response that involved in the down-regulation an ongoing Th2 (allergic) response. Within this program, 3 closely inter- related research projects and 3 cores will be directed by a team of investigators with extensive expertise in allergy, immunology, pulmonology, gene therapy and molecular biology. The proposed studies will evaluate the specific mechanisms of immune activation induced by DNA adjuvants which have been incorporated into plasmid-based vaccination vectors. This program will use advanced technologies including transgenic and gene knockout mice, phase display library, in situ hybridization, and different cloning strategies to elucidate the fundamental mechanisms relevant to the interactions among gene vaccination, the innate response, the immune system and the allergic response. Project-1 will investigate the practical requirements for an effective DNA vaccine against allergy to the house dust mite. Novel DNA vaccine vectors and new strategy of cloning cDNAs of allergens will be developed and their immunostimulatory properties will be tested in vitro and in vivo. Project-2 will explore in vivo the optimal conditions for the induction of a Th1 response by the allergen gene vaccines (generated in project-1) and will apply the biological principles operating in this system to induce a Th1 response to non-DNA-based vaccines. Project-3 will explore: a) the role of various cellular components of the immune system (e.g. NK, CD4+, CD8+ or gamma delta T cells etc.) involved in the induction and maintenance of the Th1 response by gene vaccination and b) the cytokine environment in vivo required for the observed response. These projects will be supported by a Molecular Biology Core, an Immunoassay Core and an Animal Core which will generate reagents, provide laboratory services as well as knockout or transgenic animals.