AVIAN INFLUENZA VIRUS (AIV) INFECTION IS A SERIOUS THREAT THAT CAN LEAD TO DRAMATIC LOSSES FOR THE POULTRY INDUSTRY AND IS A POTENTIAL HUMAN HEALTH RISK. AS DOMESTIC CHICKENS ARE HIGHLY SUSCEPTIBLE TO AIV, EVEN LOW PATHOGENICITY AIV (LPAIV) CAN CAUSE RESPIRATORY DISEASE AND REDUCE PERFORMANCE. BETTER UNDERSTANDING OF THE MECHANISMS BY WHICH THE CHICKEN'S INNATE IMMUNE SYSTEM RESPONDS TO AIV AND THEIR INVOLVEMENT IN HOST RESISTANCE ARE STILL NEEDED. THIS USDA-NIFA-AFRI-EWD POSTDOCTORAL FELLOWSHIP WILL INCREASE UNDERSTANDING OF RESISTANCE TO AIV INFECTION AND WILL FURTHER THE DEVELOPMENT OF AN INDEPENDENT RESEARCHER FOCUSED ON ANIMAL HEALTH AND GENOMICS. THIS PROJECT LEVERAGES WELL-CHARACTERIZED GENETIC LINES AND STATE-OF-THE-ART TECHNOLOGIES TO INVESTIGATE INNATE IMMUNE GENE EXPRESSION RESPONSES TO LPAIV AND TO IDENTIFY GENES AND PATHWAYS THAT CONTRIBUTE TO RESISTANCE TO INFECTION. WE WILL UTILIZE TWO INBRED CHICKEN LINES TO MODEL RESISTANCE AND SUSCEPTIBILITY, MEASURE GENOME-WIDEGENE EXPRESSION (THE TRANSCRIPTOME) AT THE RESOLUTION OF SINGLE CELLS, AND ASSAY SPECIFIC TARGET GENES (HIGH-THROUGHPUT QUANTITATIVE PCR) TO FURTHER COMPARE IN VIVO RESPONSES AND IN VITRO RESPONSES OF PRIMARY LUNG MACROPHAGES. THE IMMUNE RESPONSE MECHANISMS IDENTIFIED IN THIS PROJECT COULD BE USED TO EXAMINE HOST-PATHOGEN INTERACTIONS IN COMMERCIAL CHICKEN POPULATIONS, COULD INFORM RESEARCH ON GENETIC SELECTION OR IMPROVEMENT OF VACCINATIONS, AND IN THE LONG-TERM, COULD FACILITATE NEW STRATEGIES TO DECREASE THE NEGATIVE IMPACT OF AIV ON COMMERCIAL POULTRY.