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ARS Home » Pacific West Area » Pullman, Washington » Animal Disease Research » Research » Publications at this Location » Publication #211897

Title: Presence of specific MHC Class II expressed alleles associates with clinical disease in ovine progressive pneumonia virus (OPPV) infected sheep

item Hoesing, Lynn
item White, Stephen
item Mousel, Michelle
item Lewis, Gregory
item Knowles Jr, Donald

Submitted to: International Symposium on Animal Genomics for Animal Health
Publication Type: Abstract Only
Publication Acceptance Date: 6/18/2007
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A genetic tool hypothesized to predict which OPPV infected sheep will progress to debilitating clinical disease is MHC Class II Ovis aries (Ovar)-DRB1. Previously, fifteen Ovar-DRB1 beta 1 expressed alleles were identified in a ewe-lamb flock of 32 originating from an Idaho flock using RT-PCR, cloning and sequencing (Herrmann et al., 2005, Immunogenetics 57: 855-863). During further studies, eighteen additional Ovar-DRB1 beta 1 expressed alleles were identified in 383 sheep of Columbia, Rambouillet and Polypay breeds originating from the same Idaho flock. In this current study, Ovar-DRB1 allelic frequencies were calculated for the Idaho flock, and specific Ovar-DRB1 expressed alleles were examined for associations with systemic OPP provirus load, a measure of OPPV clinical disease using quantitative PCR. The most frequent Ovar-DRB1 allele was DRB1*1202 (15.7%) followed by DRB1*02032 (11.7%), DRB1*0206 (9.9%), DRB1*0403 (6.5%), DRB1*0353 (5.1%), and DRB1*0404 (5.0%). The presence of DRB1*02032 and DRB1*1101 expressed alleles significantly associated with OPP provirus loads of greater or equal to 212 copies of envelope/ug DNA (Fisher's Exact test, 2-sided p value=0.02 and p value=0.04, respectively). In contrast, the presence of DRB1*07012 expressed allele significantly associated with undetectable OPP provirus loads (Fisher's Exact test, 2-sided p value=0.01). These data indicate that the presence of DRB1*02032 and DRB1*1101 in an OPPV endemic flock may contribute in maintaining OPPV persistence.