育種・遺伝2

[II-16-29] Comparison of BLV infectivity between bovine leukemia virus susceptible and resistant cattle

*Lanlan Bai^1,2, Liushiqi Borjigin², Hirotaka Sato², Shin-Nosuke Takeshima^2,3, Tomokazu Fukuda¹, Sakurako Asaji⁴, Asako Ando^4,5, Hidetoshi Inoko⁴, Yoko Aida^2,6 (1. Graduate School of Science and Engineering, Iwate University, 2. Viral Infectious Diseases Unit, RIKEN, 3. Department of Food and Nutrition, Jumonji University, 4. GenoDiva Pharma Inc., 5. Division of Basic Medical Science and Molecular Medicine, Tokai University School of Medicine, 6. Graduate School of Agricultural and Life Sciences, The University of Tokyo)

Bovine leukemia virus (BLV) infects cattle worldwide and induces severe economic losses. The major transmission route is via infected blood. Polymorphisms of bovine lymphocyte antigen (BoLA)-DRB3 alleles are related to susceptibility to BLV proviral load (PVL). However, whether differential BoLA-DRB3 alleles affect BLV infectivity is still unclear. Here, we evaluated BLV infectivity in susceptible and resistant cattle in a three-year follow-up investigation. The BoLA-DRB3 alleles, PVLs, and infectivity were analyzed. Among tested 179 cattle, the rates of susceptible and resistant alleles were 22 % and 16%, respectively. The mean PVL of resistant cattle was significantly lower than those of susceptible and neutral cattle. Susceptible cattle showed stronger BLV infectivity than both resistant and neutral cattle. BLV-infected resistant cattle were found to be at a low risk of BLV transmission owing to weak BLV infection and low PVL. Our results show that the BoLA-DRB3 allele directly or indirectly associates with BLV infectivity. The breed selection based on resistant BoLA-DRB3 allele is an effective strategy for reducing and controlling BLV infection.