[Features of the distribution of BoLA-A antigens and alleles of the BoLA-DRB3 gene in Black Pied cattle in relation to association with leukemia].

The character of distribution of BoLA class-I antigens was studied in Black Pied cattle populations differing in status in relation to leukemia. Associative relationships of distinct antigens with resistance and susceptibility to leukemia were revealed. Using the statusmetria method, an integral estimate of predisposition to leukemia (Z) was calculated taking into consideration the contribution of each antigen in the immunogenetic status of the animal. The interval of Z values was determined, which allowed animals to be divided into groups according to resistance or susceptibility to leukemia. Alleles of the BoLA-DRB3 gene were typed in subsamples of animals with leukemia and healthy animals by the PCR-RFLP method. Twenty alleles of the gene were detected, and their frequencies were determined in both subsamples. Alleles mediating resistance of animals to leukemia (BoLA-DRB3.2*11, *23, and *28) were distributed in the group of healthy animals with frequencies of 0.079, 0.132, and 0.053, respectively; they were completely absent in animals with leukemia. The data on the estimate of animal status in relation to leukemia, which were obtained by the method of statusmetria taking in consideration the real contribution of the each class-I antigen in the detection of the disease risk (value Z), and data of allele typing by the PCR-RFLP method were shown to be in good agreement. The possibility of using BoLA class-I antigen typing in herds to determine the number of animals with leukemia was demonstrated.