Mechanism of selective tumorigenesis of B-1a cells by bovine leukemia virus infection

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K16006
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 42020:Veterinary medical science-related
• Research Institution: Azabu University
• Principal Investigator: Aihara Naoyuki 麻布大学, 獣医学部, 講師 (50821732)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 牛伝染性リンパ腫ウイルス / リンパ腫 / B-1a細胞

Outline of Final Research Achievements

Bovine lymphoma virus (BLV) is the causative agent of bovine epidemic lymphoma (EBL) in infected cattle. Although BLV can infect not only B-cell but also T-cells, monocytes, and granulocytes, BLV causes the development of B-cell lymphoma derived from CD5-positive B-1a cells. This study aimed to elucidate the mechanism of B-1a cell-selective tumorigenesis in BLV-infected cattle. B-1a cells are mainly located in fat-associated lymphoid clusters in the body cavity, therefore, pathological findings of FALCs were observed in the present study. As a result, B-1a cells were selectively proliferating at FALC in BLV-infected cattle at the asymptomatic and persistent lymphocytosis stage. Furthermore, BLV RNA expression was confirmed in the same area. These findings were not observed in the lymph node. This study indicated that the existence of selective proliferation of B-1a cells is restricted to FALC due to BLV infection.

Free Research Field

獣医病理学

Academic Significance and Societal Importance of the Research Achievements

EBLの発生は30年前の40倍以上に急増し、国内で飼養される牛約400万頭の30～40%がBLVに感染しているとされることから、EBL発症リスクを持つ牛は120万頭以上と推定される。発症機序の解明は発症予防法の確立のための喫緊の課題であり、B-1a細胞に着目した研究は新しいアプローチである。本研究により、BLV感染後、体腔内FALCにおけるB-1a細胞の選択的な増殖、BLV RNA発現が明らかになった。腫瘍化を促進する微小環境の解明は発症予防法の開発に貢献する知見である。