2009 Annual Report 1a.Objectives (from AD-416) Identify the underlying viral-specific elements of porcine reproductive and respiratory syndrome virus (PRRSV) disease pathogenesis. The goal of the study is to gain knowledge on the critical domains of PRRSV nonstructural protein 2, to assess the growth characteristics of constructed deletion mutants, to understand if the immune response of swine to the deletion mutants is altered, and to localize the protein in infected cells. 1b.Approach (from AD-416) Identify the underlying viral-specific elements of porcine reproductive and respiratory syndrome virus (PRRSV) disease pathogenesis. 1. Test the hypothesis that nsp2 harbors dispensable domains for nsp2 function. 2. Test the hypothesis that the porcine immune response will be improved by modification of nsp2 in recombinant porcine reproductive and respiratory virus (PRRSV). 3. Test the hypothesis that PRRSV nsp2 is targeted to the endosome-lysosome system. 3.Progress Report The research project was transferred from the University of Minnesota with the ARS scientist. The remaining aim on the proposal was to inoculate swine with recombinant viruses that had engineered deletions in an area of the PRRSV genome known as nonstructural protein 2 (nsp2). The ARS has completed a test growth experiment and has amplified the viruses to a quantity needed for the NRI sponsored research. Funds were transferred, by a Specific Cooperative Agreement, to South Dakota State University for virus inoculation into swine and testing of samples after the completion of the NRI animal study. Likewise, funds were transferred, by a Specific Cooperative Agreement, to the University of Minnesota for completion of immunological tests after the animal study is completed. In January of 2009, a Material Transfer Agreement was sent for University of Minnesota's approval in order to allow transfer of the mutant virus strains to South Dakota State University. We are working with the Office of Technology Transfer to resolve this issue, but until approval of the Material Transfer Agreement by the University of Minnesota, the in vivo study has been delayed.