Menin Álvaro, Bueno Natana Maria Metinoski, Hindlmayer Maria Eduarda, Reck Carolina, de Lima Nogueira Lucas, Pinto Aguinaldo Roberto, Báfica André
Department of Biosciences and One Health, Federal University of Santa Catarina, Curitibanos, SC, CEP-89520-000, Brazil.
Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina, Florianópolis, SC, CEP-88040-900, Brazil.
Sci Rep. 2025 Aug 19;15(1):30286. doi: 10.1038/s41598-025-13121-0.
Coinfections can alter the adaptive immune responses to bovine tuberculosis (bTB) and hinder accurate diagnosis; however, their effect on host immunity to Mycobacterium bovis and disease progression is not well understood. In this study, we assessed the impact of natural coinfection with bovine leukemia virus (BLV) on immune responses to M. bovis. Among 108 cattle examined, those coinfected with BLV showed a significantly higher intragranulomatous mycobacterial burden and more severe pathological lesions compared to animals infected with M. bovis alone. Additionally, coinfected animals demonstrated a granulomatous response characterized by reduced lymphocyte populations, increased neutrophil infiltration, and diminished granuloma encapsulation, suggesting a compromised antimycobacterial immune response. Supporting this hypothesis, BLV-infected cattle exposed to mycobacterial antigens displayed impaired delayed-type hypersensitivity (type IV hypersensitivity) to a purified protein derivative of M. bovis as well as reduced antibody response. These findings indicate that BLV coinfection influences the immunopathogenesis of bTB, exacerbates disease progression in cattle naturally infected with M. bovis, and may reduce the predictive reliability of diagnostic methods used in bTB control programs.
混合感染可改变对牛结核病（bTB）的适应性免疫反应并妨碍准确诊断；然而，它们对宿主针对牛分枝杆菌的免疫力和疾病进展的影响尚不清楚。在本研究中，我们评估了自然感染牛白血病病毒（BLV）的混合感染对针对牛分枝杆菌免疫反应的影响。在检查的108头牛中，与仅感染牛分枝杆菌的动物相比，感染BLV的混合感染牛表现出明显更高的肉芽肿内分枝杆菌负荷和更严重的病理病变。此外，混合感染动物表现出一种肉芽肿反应，其特征是淋巴细胞数量减少、中性粒细胞浸润增加和肉芽肿包囊减少，提示抗分枝杆菌免疫反应受损。支持这一假设的是，暴露于分枝杆菌抗原的感染BLV的牛对牛分枝杆菌纯化蛋白衍生物的迟发型超敏反应（IV型超敏反应）受损以及抗体反应降低。这些发现表明，BLV混合感染会影响bTB的免疫发病机制，加剧自然感染牛分枝杆菌的牛的疾病进展，并可能降低bTB控制计划中使用的诊断方法的预测可靠性。
