Núcleo Aplicado à Produção e Sanidade da Glândula Mamária, Departamento de Ciências Veterinárias, Centro de Ciências Agrárias, Universidade Federal da Paraíba, 58397-000, Areia, Brazil.
Veterinary Clinical Immunology Research Group, Departamento de Clínica Médica, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, 05508-270, São Paulo, Brazil.
BMC Vet Res. 2021 Aug 25;17(1):282. doi: 10.1186/s12917-021-02989-5.
The present study explored the viability of bovine milk macrophages, their intracellular production of reactive oxygen and nitrogen species (RONS), and their phagocytosis of Staphylococcus aureus, as well as the profile of lymphocytes, from healthy udder quarters and udder quarters infected by Corynebacterium bovis. The study included 28 healthy udder quarters from 12 dairy cows and 20 udder quarters infected by C. bovis from 10 dairy cows. The percentages of macrophages and lymphocytes were identified by flow cytometry using monoclonal antibodies. Macrophage viability, RONS production, and S. aureus phagocytosis were evaluated by flow cytometry.
Milk samples from quarters infected with C. bovis showed a lower percentage of macrophages but an increased number of milk macrophages per mL and a higher percentage of macrophages that produced intracellular RONS and phagocytosed S. aureus. No effect of C. bovis infection on macrophage viability was found. Udder quarters infected by C. bovis showed a higher percentage of T cells and CD4 T lymphocytes, but no effect was found on the percentage of CD8 CD4 T, CD8 CD4 T, or B lymphocytes.
Thus, our results corroborate, at least in part, the finding that intramammary infections by C. bovis may offer protection against intramammary infections by major pathogens.
本研究探讨了健康乳区和感染棒状杆菌乳区牛乳腺巨噬细胞的活力、细胞内活性氧和氮物质（RONS）的产生以及对金黄色葡萄球菌的吞噬作用，以及淋巴细胞的特征。该研究包括来自 12 头奶牛的 28 个健康乳区和来自 10 头奶牛的 20 个感染棒状杆菌的乳区。使用单克隆抗体通过流式细胞术鉴定巨噬细胞和淋巴细胞的百分比。通过流式细胞术评估巨噬细胞活力、RONS 产生和金黄色葡萄球菌吞噬作用。
感染棒状杆菌的乳区牛奶样本中巨噬细胞的百分比较低，但每毫升牛奶中巨噬细胞的数量增加，产生细胞内 RONS 和吞噬金黄色葡萄球菌的巨噬细胞的百分比增加。未发现棒状杆菌感染对巨噬细胞活力有影响。感染棒状杆菌的乳区 T 细胞和 CD4 T 淋巴细胞的百分比较高，但 CD8 CD4 T、CD8 CD4 T 或 B 淋巴细胞的百分比没有影响。
因此，我们的结果至少部分证实了以下发现，即棒状杆菌的乳腺内感染可能为主要病原体的乳腺内感染提供保护。
