Milk lymphocyte profile and macrophage functions: new insights into the immunity of the mammary gland in quarters infected with Corynebacterium bovis

• Published in: BMC veterinary research Vol. 17; no. 1; pp. 1 - 282
• Main Authors: Silva, Vitória M, Souza, Marina T, Blagitz, Maiara G, Souza, Fernando N, Batista, Camila F, Alves, Alexandre J, Fernandes, Artur C. C, Sanchez, Eduardo M. R, Ordinola-Ramirez, Carla M, da Costa, Luciana, Della Libera, Alice M. M. P
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 25-08-2021; BioMed Central; BMC
• Subjects: Actinomycetales infections; Animal lactation; Bacteria; Cattle; CD4 antigen; CD8 antigen; Corynebacterium; Cow's milk; Dairy cattle; Dairy cow; Development and progression; Diseases; Flow cytometry; Health aspects; Immune response; Infections; Intracellular; Lymphocytes; Lymphocytes B; Lymphocytes T; Macrophages; Mammary gland; Mammary glands; Mastitis; Microbiota; Milk; Monoclonal antibodies; Neutrophils; Pathogens; Phagocytes; Phagocytosis; Reactive nitrogen species; Reactive oxygen species; Staphylococcus aureus; T lymphocyte; Udder; Viability; Brazil
• ISSN: 1746-6148; 1746-6148
• DOI: 10.1186/s12917-021-02989-5

Backgrounds 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. Results 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.sup.+ T lymphocytes, but no effect was found on the percentage of CD8.sup.+ CD4.sup.- T, CD8.sup.- CD4.sup.- T, or B lymphocytes. Conclusions 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. Keywords: Immune response, Phagocytes, T lymphocyte, Mastitis, Milk, Dairy cow