Association between genes Bola-DRB3.2*8 and Bola-DRB3.2*12 with resistance and Bola-DRB3.2*16 with susceptibility to infection by bovine leukemia virus

The bovine leukemia virus (blv) is a retrovirus that affects the immune system of cattle as their target cells are b lymphocytes. some polymorphisms at the bola-drb 3.2 gene have been associated with resistance/susceptibility to diseases. the objective of this research was to determine the polymorphisms at the bola-drb 3.2 gene and associate them with resistance (r),neutrality (n) or susceptibility (s) to blv in a holstein cow population.500 blood samples were taken. nested pcr was performed for detecting blv virus and pcr-rflp was performed to identify alleles of gene bola-drb 3.2. susceptibility was determined using odds ratio (or) and p value. according to their genotype,cows were classified in homozygous (r/r,n/n,or s/s) and heterozygous (r/n,r/s,n/s). blv molecular prevalence was 44%. the most frequent allele was bola-drb3.2*22 (16.8%),alleles associated with resistance to blv were bola-drb3.2*8 (or=1.489; p < 0.10) and bola-drb3.2*12 (or=3.897; p < 0.10) and allele bola-drb3.2*16 (or=0.710; p < 0.10) was associated with susceptibility. allele bola-drb3.2*8 had the highest allelic frequency for negative cows (0.19). 63.7% of cows with genotype rn and 70% of cows with genotype rr were resistant to infection by blv. alleles r and s have a dominant effect on allele n (p < 0.05). the use of reliable diagnostic techniques in conjunction with identification of resistant or susceptible animals can monitor the progress of the disease in dairy herds. alleles bola-drb3.2*8 and *12 were positively related to the disease and therefore cows have low risk of infection,unlike allele bola-drb3.2*16 which was negatively related and animals have high risk for the disease. © 2016 pvj. all rights reserved.