Toll-like receptor 6 gene polymorphisms increase the risk of bovine tuberculosis in Chinese Holstein cattle

Our present study aimed to investigate the effect of four SNPs (G1793A, C1859A, A1980G, G1934A) in toll-like receptor 6 (TLR6) on bovine tuberculosis (bTB) resistance in a case–control study. A total of 603 Chinese Holstein cattle (264 from a dairy farm of Henan province, 339 from Hubei province) were selected to analyze the genotype of TLR6 gene by PCR-RFLP. Genotype frequencies of C1859A and A1980G site differed significantly between bTB-infected and non-infected cows (χ2 = 6.062, P = 0.048 and χ2 = 6.749, P = 0.034, respectively). Relative risk of tuberculosis incidence result showed that genotypes of AA or CA had greater relative risk (OR = 2.730, 95%CI = 0.869–8.573; OR = 1.547, 95CI% = 0.803–2.982, respectively) than those with genotype CC at C1859A site between bTB-infected and non-infected animals. Genotypes of GG or GA had greater relative risk (OR = 2.986, 95%CI = 1.245–7.165; OR = 1.582, 95%CI = 0.734–3.409, respectively) than those with genotype AA at A1980G site. No significant association can be inferred from G1793A and G1934A polymorphism site. The present study suggests that variants in the TLR6 gene are associated with susceptibility to bTB and the TLR6 gene may be considered as a candidate gene for bTB resistance.