Α-lactalbumin Gene and Susceptibility of Lymphocytes to Infections with Bovine Leukaemia Virus and to Apoptosis in Naturally Infected Cows

A study was undertaken to analyse the effect of polymorphism of α-lactalbumin (ALA) gene at position -1689 on the susceptibility of lymphocytes to the infection with bovine leukaemia virus (BLV) and to undergoing apoptosis during the first three months after calving. The experiments covered 97 Black-and-White breed cows, aged 3–8 years, from three herds. The infection with BLV was diagnosed on the basis of the presence of the p24 protein of the virus identified by means of the fluorescent antibody test in peripheral blood lymphocytes. The BLV-positive and apoptotic cells were registered with the use of a fluorescence microscope. Analyses of white blood cell counts enabled separating the BLVinfected cows into groups with the aleukaemic form and with persistent lymphocytosis. The results obtained demonstrated a relationship between polymorphism of ALA gene and the susceptibility of lymphocytes to BLV infections and to undergoing apoptosis. The current study, together with the authors’ previous research, suggests the possibility of ALA gene participation in mechanisms of BLV infection pathogenesis.