Association of BLV-infection profiles with alleles of BoLA DRB3.2 gene

JULIARENA M.A., POLI M., SALA L., CERIANI C., GUTIERREZ S., DOLCINI G., RODRÍGUEZ E., MARIÑO B., RODRÍGUEZ-DUBRA C. & ESTEBAN E. N.

ANIMAL GENETICS

International Society of Animal Genetics

Año: 2008 vol. 39 p. 432 - 438

0268-9146

Bovine leukemia virus (BLV) causes lymphosarcoma and persistent lymphocytosis (PL). Some Class II MHC gene polymorphisms have been associated with resistance and susceptibility to the development of lymphosarcoma, PL or a reduced number of circulating BLV-infected lymphocytes. In a previous study, 230 BLV-infected Holstein cattle were classified into two infection profiles characterized as low and high proviral load (LPL and HPL). The influence of the polymorphism of BoLA DRB*3.2 gene on these animals was examined. The genotyping was carried out by PCR-RFLP and PCR-SSO. The association between BoLA DRB*3.2 alleles and BLV-infection profile was determined as the odds ratio (OR). By PCR-SSO 2 subtypes of the allele *11 were found (ISAG*0901 and *0902). Allele ISAG *0902 showed a stronger association to LPL profile (OR = 8.24; p < 0.0001) than allele *11 itself (OR = 5.82; p < 0.0001). Allele ISAG*1701 (*12) also showed significant association to LPL profile (OR = 3.46; p < 0.0055). Only one allele, ISAG*1501 or 03 (*16) showed significant association to HPL (OR = 0.36; p < 0.0005). DRB*3.2 alleles were assigned to 3 categories: Resistant (R), Susceptible (S) and Neutral (N). Based on their DRB3 genotyping, cattle were classified as homozygous or heterozygous. The R/R and R/N genotypes were associated with LPL profile, while the S/S and N/S genotypes were associated with HPL profile. The R/S genotype could not be associated with any particular profile.   Our results show that allele ISAG*0902 appears to be the best marker of BLV resistance in Holstein cattle.