2010 Annual Report 1a.Objectives (from AD-416) Thorough investigation of the immunogenetic responses involved in host-pathogen interactions in Avian Influenza will lead to better understanding of genetic countrol of host response to AI and the identification of immunogenetic mechanisms which will facilitate the development of novel vaccination strategies against AI. 1b.Approach (from AD-416) APDL plans to apply avian cDNA intestinal IEL microarray (AVIELA) chips which were developed in Dr. Lillehoj's laboratory at BARC, ARS to characterize the differential immune response patterns of different genetic breeds of broiler chickens with different disease phenotypes. 3.Progress Report This grant was established to investigate host innate immunity against respiratory viral infections. In this reporting period, we used an avian influenza (AI) infection model that we developed last year to investigate host cytokine response. Korean native chickens were experimentally infected with H9N2 low pathogenic AI virus (A/chicken/Korea/MS96/1996(MS96)) and their cytokine responses were measured using a quantitative real time PCR. The results are being summarized. In another study, we immunosuppressed chickens using dexamethasone (DEX) to increase the severity of H9N2 LPAI infection. Virus load and host immune responses of normal and DEX-immunosuppressed chickens are being evaluated. Progress is monitored by regular meetings, written progress reports and regular teleconferences.