Submitted to: Expression Genetics Differential Display
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2017
Publication Date: N/A
Technical Abstract: Marek's disease (MD) is a herpesvirus-induced lymphoma in chickens with a significant economic impact to the poultry industry, costing the industry over $1 billion annually worldwide. MD is controllable by vaccination and improving genetic resistance in the host. Two inbred layer lines, matched at the MHC locus, have been bred for high (Line 6-3) and low (Line 7-2) genetic resistance, respectively, to MD. We identified large differences in TCR Vbeta usage in the peripheral T cells of these bird lines by flow cytometry. In the chicken, two families of Vbeta genes have been identified (Vbeta-1 and Vbeta-2). While TCR Vbeta-1+ T cells are more prevalent in both lines than TCR Vbeta-2+, MD-resistant birds used the Vbeta-2 TCR at very low rates. During infection with Marek’s disease virus, Vbeta usage on CD4+ T cells was stable in both lines until day 21 post-challenge, when lymphomagenisis is occuring. Conversely, an increased bias towards Vbeta-1 TCRs was found as early as day 8 in CD8+ splenocytes in the MD-resistant chicken only. We hypothesize that differences in TCR repertoire may play a direct role in CD8+ T cell-mediated resistance to MD-induced tumors. We are comparing TCR usage in an additional MD resistance model which varies only at the MHC locus; as well as in a panel of Lines 6-3x7-2 recombinant strains, in order to further establish the importance of TCR usage in MD and to identify genomic regions which influence TCR expression in the chicken.