Objective:
1. Determine protective immune responses in genetically defined swine to better understand innate resistance mechanisms against FMD and CSF viral infections. 2. Determine variations in the molecular pathogenesis of endemic and exotic viral diseases in the same taxonomic amily that will lead to the discovery of effective biotherapeutics to prevent viral transmission and viral persistance. 3. Analyze the structural features of polymerase-drug interactions to design effective anti-viral therapeutics against FMD and CSF.

Approach:
1. In this objective, we will generate ¿knockout¿ swine with targeted mutations in important antiviral defense molecules and immune effector cells and evaluate the immune response to viral antigens in genetically defined swine to better understand innate resistance against viral infections such as those caused by FADs. Follow-up with viral infection experiments will occur after the animals have been transferred to PIADC. Over the next 4 years, our specific aims are to generate 3-4 knockout swine models, each of which will have targeted mutations in specific components of the immune system critical to Foot and Mouth Disease Virus (FMDV) and Classical Swine Fever Virus (CSFV) antiviral defense. Our overall hypothesis is that these mutant swine will have increased susceptibility to FMDV and CSFV due to defects in defense mechanisms. Importantly, these mutant swine will facilitate the study of signaling and vaccine response pathways and identification of alternative antiviral defense pathways. A better understanding of antiviral defense will lead to development of new and improved strategies for vaccine development and other approaches to disease control. These studies have tremendous potential to advance not only CSF and FMD research, but any naturally occurring viral disease of swine. In addition, because swine share anatomic and physiologic characteristics with humans, these mutants will have far reaching utility in biomedical research. 2. Determine the primary immune factors and viral nonstructural proteins associated with the virulence of Pestiviruses by utilizing the BVDV cp and ncp biotypes in an in vitro culture system. It is anticipated that investigation of pathogenesis and host-pathogen interactions at the cellular level in this model of endemic disease will lead to the discovery of valuable tools for breaking viral persistence. 3. Using purified viral polymerases, we propose to develop novel compounds that inhibit replication of important FAD pathogenic viruses, FMDV and CSFV, and the domestically important Pestivirus BVDV. We will analyze structural features of polymerase-drug interactions to design effective antiviral therapeutics.