Kinetic Study of BLV Infectivity in BLV Susceptible and Resistant Cattle in Japan from 2017 to 2019

• Published in: Pathogens (Basel) Vol. 10; no. 10; p. 1281
• Main Authors: Bai, Lanlan, Borjigin, Liushiqi, Sato, Hirotaka, Takeshima, Shin-Nosuke, Asaji, Sakurako, Ishizaki, Hiroshi, Kawashima, Keiji, Obuchi, Yuko, Sunaga, Shinji, Ando, Asako, Inoko, Hidehito, Wada, Satoshi, Aida, Yoko
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 05.10.2021; MDPI
• Subjects: Alleles; Antigens; BLV; BoLA-DRB3 allele; Bovine leukosis; Cattle; Dairy industry; Disease; Disease transmission; Genomes; Health risks; horizontal transmission; Infections; Infectivity; Leukemia; Leukosis; Lymphocytes; Milk; Polymorphism; proviral load; Risk; susceptible; syncytium formation; Viruses; Japan
• ISSN: 2076-0817; 2076-0817
• DOI: 10.3390/pathogens10101281

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis. Polymorphism in bovine lymphocyte antigen (BoLA)-DRB3 alleles is related to susceptibility to BLV proviral load (PVL), which is a useful index for estimating disease progression and transmission risk. However, whether differential BoLA-DRB3 affects BLV infectivity remains unknown. In a three-year follow-up investigation using a luminescence syncytium induction assay for evaluating BLV infectivity, we visualized and evaluated the kinetics of BLV infectivity in cattle with susceptible, resistant and neutral BoLA-DRB3 alleles which were selected from 179 cattle. Susceptible cattle showed stronger BLV infectivity than both resistant and neutral cattle. The order of intensity of BLV infectivity was as follows: susceptible cattle > neutral cattle > resistant cattle. BLV infectivity showed strong positive correlation with PVL at each testing point. BLV-infected susceptible cattle were found to be at higher risk of horizontal transmission, as they had strong infectivity and high PVL, whereas BLV-infected resistant cattle were low risk of BLV transmission owing to weak BLV infection and low PVL. Thus, this is the first study to demonstrate that the BoLA-DRB3 polymorphism is associated with BLV infection.