Milk lymphocyte profile and macrophage functions: new insights into the immunity of the mammary gland in quarters infected with Corynebacterium bovis.
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+ T lymphocytes, but no effect was found on the percentage of CD8+ CD4- T, CD8- CD4- 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.
['Silva|Vitória M|VM|', 'Souza|Marina T|MT|', 'Blagitz|Maiara G|MG|', 'Souza|Fernando N|FN|', 'Batista|Camila F|CF|', 'Alves|Alexandre J|AJ|', 'Fernandes|Artur C C|ACC|', 'Sanchez|Eduardo M R|EMR|', 'Ordinola-Ramirez|Carla M|CM|', 'da Costa|Luciana|L|', 'Della Libera|Alice M M P|AMMP|']
D000818:Animals D002417:Cattle D003352:Corynebacterium D005260:Female D008214:Lymphocytes D008264:Macrophages D008414:Mastitis, Bovine D008892:Milk D010587:Phagocytosis D026361:Reactive Nitrogen Species D017382:Reactive Oxygen Species D013211:Staphylococcus aureus
Milk Dairy cow T lymphocyte Immune response Mastitis Phagocytes