Genetics of anti-EHV antibody responses in a horse population.

Individual variation in immune responses to herpesviruses was observed in various species. Here, associations between polymorphic molecular markers and life-long anti-EHV-1/4 antibody immune responses were analyzed in a model EHV-infected population of the Old Kladruber horses. Two-dimensional analysis including overall mean titers and titer dynamics expressed by differences between spring and autumn titers allowed identification of low-responders. 50 randomly selected microsatellites and nine single nucleotide polymorphisms in nine immunity-related candidate genes were genotyped. Due to differences (p<0.001) in antibody titers between two color varieties of Old Kladruber horses, separate association studies were performed in the two sub-populations by using the Fisher's exact test. In black horses, the interleukin 4 receptor and MxA protein coding genes, and the microsatellite TKY325 were associated with the responder status. In the grey population, the microsatellite TKY343 showed significant association with anti-EHV antibody responsiveness after Bonferroni corrections.