Function of milk polymorphonuclear neutrophil leukocytes in bovine mammary glands infected with Corynebacterium bovis

Autor(es)

Blagitz, M. G. ^[1] ; Souza, F. N. ^[2] ; Santos, B. P. ^[1] ; Batista, C. F. ^[1] ; Parra, A. C. ^[1] ; Azevedo, L. F. F. ^[1] ; Melville, P. A. ^[3] ; Benites, N. R. ^[3] ; Della Libera, A. M. M. P. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Med Vet & Zootecnia, Dept Clin Med, BR-05508270 Sao Paulo - Brazil

^[2] Univ Fed Minas Gerais, Escola Vet, Dept Vet Prevent Med, BR-31270010 Belo Horizonte, MG - Brazil

^[3] Univ Sao Paulo, Fac Med Vet & Zootecnia, Dept Med Vet Prevent & Saude Anim, BR-05508270 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF DAIRY SCIENCE; v. 96, n. 6, p. 3750-3757, JUN 2013.
• Citações Web of Science: 17

Resumo

Corynebacterium bovis is one of the most commonly isolated bacteria from aseptically collected bovine milk samples. The objective of the current study was to characterize the bovine innate immune response by evaluating milk polymorphonuclear neutrophilic leukocytes (PMNL) in mammary glands infected with C. bovis. Twenty quarters infected with C. bovis and 28 culture-negative quarters (with milk somatic cell count <1 x 10(5) cells/mL) were used. The percentages of milk PMNL and the PMNL expression of L-selectin (CD62L), beta(2)-integrin (CD11b), and one of the endothelial-selectin ligands (CD44), as well as the levels of intracellular reactive oxygen species (ROS) and the phagocytosis of Staphylococcus aureus, were evaluated by flow cytometry. The apoptosis and necrosis rates of the PMNL were quantified using dual-color flow cytometry with fluorescein-labeled annexin and propidium iodide. The present study revealed a higher percentage of PMNL in the milk from C. bovis-infected quarters, although no significant differences were found in levels of CD44, CD62L, or CD11b expression among the PMNL. A lower percentage of apoptotic PMNL was observed in C. bovis-infected quarters, as well as higher percentages of viable PMNL and of PMNL that produced intracellular ROS. However, no alterations were observed in phagocytosis of Staph. aureus by the PMNL or in intensity of intracellular ROS production by PMNL. Thus, results from this investigation of the PMNL function support, at least in part, the fact that intramammary infections by C. bovis may offer protection against intramammary infections by other bacteria. (AU)

• Processo FAPESP: 09/50672-0 - Avaliação funcional dos leucócitos sanguíneos e lácteos de vacas naturalmente infectados pelo vírus da leucose dos bovinos
• Beneficiário: Alice Maria Melville Paiva Della Libera
• Modalidade de apoio: Auxílio à Pesquisa - Regular