Location: Foreign Animal Disease Research2012 Annual Report
1a. Objectives (from AD-416):
To improve Foot-and-Mouth Disease Virus (FMDV) vaccine potency and duration of immunity, ARS, PIADC and the University of Vermont (UV) 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):
ARS, PIADC in cooperation with the University of Copenhagen is developing state of the art technology for analysis of FMDV vaccine performance in cattle. The product of this collaboration, MHC tetramers for tracking T cell responses to vaccination, will be used to analyze genetically defined cattle. The University of Vermont collaborators maintain a genetically homogenous herd of Holstein cattle that make it possible to use the tetramer technology to analyze the response to vaccination with FMDV new vaccines. ARS, PIADC will collaborate with UV faculty to analyze responses to infection of these cattle with FMDV and mastitis.
3. Progress Report:
The major histocompatibility complex (MHC) class I and class II genes are critical in the T-cell mediated immune response to intracellular pathogens including viruses (class I MHC) and the adaptive immune response mediated through antigen presenting cells (class II MHC). The bovine class I and class II gene structure and sequence diversity are poorly understood, representing an obstacle in our understanding of antigen specific responses to pathogens and vaccine candidates. This collaboration seeks to determine allele diversity and frequency of the MHC class I genes in a herd of pure-bred registered Holstein dairy cattle (University of Vermont Research Herd). The planned experiments involve tissue typing the MHC of Holstein dairy cattle and developing tools to study the T cell response to Foot and Mouth Disease (FMD) virus. During FY 2012, the analysis of bovine leukocyte antigens (BoLA) Class I expression in 81 Holstein cattle from Nordic Farm, a UVM Dairy Center of Excellence Research herd, has identified 9 dominant alleles that are expressed in 23 to 44 percent of animals tested. Expression of these alleles has been confirmed by cloning and sequenceing of BoLA class I genes in 17 animals. Overall 99 percent of animals tested are positive for at least one of these alleles. Further patterns of allelic expression are being identified in individual animals contributing to our understanding of class I gene expression. We have also completed class I expression typing for 15 bovine primary fibroblast cell lines and 4 bovine immortalized epithelial cell lines. We have synthesized 6 class I molecules and an additional 5 molecules are in the pipeline for synthesis. At least 4 of these BoLA class I molecules will be used in peptide binding and cytotoxic lymphocyte (CTL) response assays. This panel of 11 BoLA class I molecules will be made available as a resource to other scientists. We have successfully transferred reagents and technologies and adapted new technologies for the development of key tools to be used in immune response assays. Specifically we have transferred the gene constructs and applied methods for recombinant protein expression of a panel of bovine cytokines using an adenovirus expression system. We have demonstrated biological activity of these cytokines and established a pipeline for production of monoclonal antibodies that recognize these lymphocyte markers. During FY 2012 the recombinant replication defective adenoviral vector expression systems have been transferred from ARS, PIADC to University of Vermont. MHC/peptide binding analysis has been transferred from the collaborators at University of Copenhagen to University of Vermont. No publications have been produced during FY 2012.