DETECTION OF A COMMON BOLA-DRB3 DELETION BY SEQUENCE-SPECIFIC OLIGONUCLEOTIDE TYPING

The bovine MHC class II allele BoLA-DRB32A has an amino acid deletion of unknown function at codon 65 in the second exon, which codes for t he antigen-binding site. Sequence-specific oligonucleotides were desig ned based on published nucleotide sequences on BoLA-DRB3 alleles, and used to detect this deletion in 51 Hereford cattle. Probes 65+ and 65- detect the presence or absence of codon 65 respectively. Oligonucleot ide probes were labelled with Digoxigenin (DIG), hybridized to dot blo ts of BoLA-DRB3 exon 2 polymerase chain reaction (PCR) product, and de tected by chemiluminescence. Of the 51 animals screened, two were homo zygous and 11 were heterozygous for the deletion at codon 65. The meth odology described here provides the necessary tools to screen rapidly for this deletion in a large number of animals in order to study its e ffect on antigen binding and immune response.