PECULIARITIES OF DISTRIBUTION OF BOLA-A A NTIGENS 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 leuke mia. Associative relationships of distinct antigens with resistance an d susceptibility to leukemia were revealed. Using the statusmetria met hod, an integral estimate of predisposition to leukemia (Z) was calcul ated taking into consideration the contribution of each antigen in the immunogenetic status of the animal. The interval of Z values was dete rmined, which allowed animals to be divided into groups according to r esistance 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 mediati ng resistance of animals to leukemia (BoLA-DRB3.211, *23, and *28) we re distributed in the group of healthy animals with frequencies of 0.0 79, 0.132, and 0.053, respectively; they were completely absent in ani mals with leukemia. The data on the estimate of animal status in relat ion to leukemia, which were obtained by the method of statusmetria tak ing in consideration the real contribution of the each class-I antigen in the detection of the disease risk (value Z), and data of allele ty ping by the PCR-RFLP method were shown to be in good agreement. The po ssibility of using BoLA class-I antigen typing in herds to determine t he number of animals with leukemia was demonstrated.