2011 Annual Report 1a.Objectives (from AD-416) To improve Foot-and-Mouth Disease Virus (FMDV) vaccine potency and duration of immunity, we will study the cellular immune response to infection and the ability to refine the killed virus vaccine for FMDV or the recombinant empty capsid vaccine. The objective of this agreement is to analyze T cell responses to FMDV infection in swine and cattle. 1b.Approach (from AD-416) The state of the art for analysis of the cellular immune response of T lymphocytes to vaccination is: identification of T cell epitopes, mapping of those epitopes to the presenting transplantation antigens known as histocompatibility complex (MHC) molecules and developing MHC tetramers for tracking T cell responses. This technology is used extensively in laboratory mice but is expensive in a genetically diverse human population. Even given the expense, the technology is being applied in the clinic more and more often. Our preliminary studies indicate common cattle breeds, such as Holstein, can be analyzed using this technology. The University of Copenhagen will generate the information required to design and test MHC tetramers for analysis of cellular immune reponse to Foot-and-Mouth Disease Virus(FMDV). ARS, PIADC will utilize this information to analyze responses of cattle and swine to vaccination and FMDV infection. 3.Progress Report Class I MHC/FMDV peptide tetramers were made for staining T cells from FMDV vaccinated animals (from SLA-1*0401 and SLA-2*04:01) and showed, of 20 peptides bound by both class I proteins, only one tetramer stained T cells from vaccinated pigs. This shows that there is an immunodominant epitope of FMDV responsed to by pigs with this genetic make up. In addition, we developed a screening method to determine the expression of class I MHC genes in the experimental herd of Holsteins at the University of Vermont (UVM). Finally, we identified 6 class II MHC gene products that account for over 90% of the MHC II genes expressed in the experimental herd at UVM, and the proteins for the first 2 of these are being generated at University of Copenhagen for further analysis in the coming year. This project was monitored through email and telephone exchange as well as site visits to ARS, PIADC. In addition, a PIADC postdoctoral collaborator and a University of Vermont PhD student spent 4 weeks in the Copenhagen laboratory learning the process of using the bioinformatics for MHC peptide binding prediction and making tetramers for analysis of T cell responses.