Enzootic bovine leukemia is a late-onset, neoplastic infection caused by the bovine leukemia virus (BLV). BLV infection hinders the function of the immune system and induces other diseases, which negatively affects the performance and health of the infected cows. As the first line of defense against invading foreign pathogenic microorganisms, polymorphonuclear neutrophil (PMN) plays a vital role in the immune system of dairy cows. However, research on the effect of BLV infection on the immune function of PMN in dairy cows is scarce. Therefore, this experiment aimed to elucidate the effects and effect mechanisms of BLV infection on the immune function of PMN in dairy cows with different BLV provirus loads by detecting the chemotaxis, migration, adhesion, phagocytosis, respiratory burst function, and the formation of NETs. The experimental results showed that BLV infection had no significant effect on the phagocytosis of PMN but inhibited their migration and respiratory burst function, and the effects were closely related to the BLV provirus load. Under high BLV provirus load, PMN produced large amounts of NETs, chemokine CXCL7, adhesion molecule CD18, and pro-inflammatory factors IL-8 and TNF-α, triggering inflammatory responses, and tissue damage. The results of this study will help reveal the reason why BLV infection causes the high incidence of mammary gland inflammation in dairy cows.

地方性牛白血病是由牛白血病病毒 (BLV) 引起的迟发性肿瘤感染。BLV 感染会阻碍免疫系统的功能并诱发其他疾病，从而对受感染奶牛的生产性能和健康产生负面影响。作为抵御外来病原微生物入侵的第一道防线，多形核中性粒细胞（PMN）在奶牛的免疫系统中起着至关重要的作用。然而，BLV感染对奶牛PMN免疫功能影响的研究很少。因此，本实验旨在通过检测趋化性、迁移、粘附、吞噬、呼吸爆发功能和NETs的形成，阐明BLV感染对不同BLV原病毒载量奶牛PMN免疫功能的影响和作用机制。实验结果表明，BLV感染对PMN的吞噬作用无明显影响，但会抑制其迁移和呼吸爆发功能，其影响与BLV原病毒载量密切相关。在高 BLV 原病毒载量下，PMN 产生大量 NET、趋化因子 CXCL7、粘附分子 CD18 和促炎因子 IL-8 和 TNF-α，引发炎症反应和组织损伤。本研究结果将有助于揭示BLV感染导致奶牛乳腺炎症高发的原因。趋化因子 CXCL7、粘附分子 CD18 和促炎因子 IL-8 和 TNF-α，引发炎症反应和组织损伤。本研究结果将有助于揭示BLV感染导致奶牛乳腺炎症高发的原因。趋化因子 CXCL7、粘附分子 CD18 和促炎因子 IL-8 和 TNF-α，引发炎症反应和组织损伤。本研究结果将有助于揭示BLV感染导致奶牛乳腺炎症高发的原因。