The bovine lymphocyte antigen -BoLA--DRB3 gene encodes cell surface glycoproteins that initiate immune responses by presenting processed antigenic peptides to CD4+ T helper cells. DRB3 is the most polymorphic bovine MHC class II gene which encodes the peptide-binding groove. Since different alleles favour the binding of different peptides, DRB3 has been extensively evaluated as a candidate marker for associations with various bovine diseases and immunological traits. For that reason, the genetic diversity of the bovine class II DRB3 locus was investigated by polymerase chain reaction-restriction fragment length polymorphism method -PCR-RFLP-. This study describes genetic variability in the BoLA-DRB3 in Iranian Sistani cattle. Iranian Sistani Cattle -n=150- were genotyped for bovine lymphocyte antigen -BoLA--DRB3.2 alleles by polymerase chain reaction and restriction fragment length polymorphism method. Bovine DNA was isolated from aliquots of whole blood. A two-step polymerase chain reaction followed by digestion with restriction endonucleases RsaI, HaeIII and BstX2I was conducted on the DNA of Iranian Sistani Cattle. In the studied herd, we identified 23 alleles. The allele BoLA-DRB3.2*34 occurred at the highest frequency of 19.33%. In this study Five alleles -BoLA-DRB3.2*34, *8, *15, *21, and *11- accounted for almost 71% of the total alleles observed to be present in the Sistani Cattle. The result obtained in the present study demonstrated that the BoLA DRB3.2 locus is highly polymorphic in the Iranian Sistani Cattle.

Keywords