The neutrophil function and lymphocyte profile of milk from bovine mammary glands infected with Streptococcus dysgalactiae

Author(s):Show less -

Blagitz, Maiara G. ^[1] ; Souza, Fernando N. ^[2] ; Batista, Camila F. ^[1] ; Azevedo, Luis Fernando F. ^[1] ; Benites, Nilson Roberti ^[3] ; Melville, Priscilla Anne ^[3] ; Diniz, Soraia A. ^[2] ; Silva, Marcos X. ^[2] ; Haddad, Joao Paulo A. ^[2] ; Heinnemann, Marcos Bryan ^[3] ; Cerqueira, Monica M. O. P. ^[4] ; Della Libera, Alice M. M. P. ^[1]

Affiliation

^[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

^[4] Univ Fed Minas Gerais, Escola Vet, Dept Tecnol & Inspecao Prod Origem Anim, BR-31270010 Belo Horizonte, MG - Brazil

• Document type: Journal article
• Source: JOURNAL OF DAIRY RESEARCH; v. 82, n. 4, p. 460-469, NOV 2015.
• Web of Science Citations: 7

Abstract

Streptococcus dysgalactiae is a bacterium that accounts for a notable proportion of both clinical and subclinical intramammary infections (IMIs). Thus, the present study explores the function of milk neutrophils and the lymphocyte profile in mammary glands naturally infected with Streptococcus dysgalactiae. Here, we used 32 culture-negative control quarters from eight clinically healthy dairy cows with low somatic cell counts and 13 S. dysgalactiae-infected quarters from six dairy cows. Using flow cytometry, we evaluated the percentage of milk monocytes/macrophages and neutrophils, expression of CD62L, CD11b and CD44 by milk neutrophils, the levels of intracellular reactive oxygen species (ROS) production and phagocytosis of Staphylococcus aureus by milk neutrophils, and neutrophil viability. Furthermore, the percentages of B cell (CD21(+)) and T lymphocyte subsets (CD3(+)/CD4(+)/CD8(-); CD3(+)/CD8(+)/CD4(-); and CD3(+)/CD8(-)/CD4(-)), and the expression of CD25 by T milk lymphocytes (CD3(+)) and T CD4(+) milk cells were also assessed by flow cytometry using monoclonal antibodies. The present study showed a higher SCC and percentage of milk neutrophils, and a decrease in the percentage of milk monocytes/macrophages from S. dysgalactiae-infected quarters when compared to uninfected ones. We also observed a higher expression of CD11b by milk neutrophils and a tendency toward a decrease in neutrophil apoptosis rate in S. dysgalactiae-infected quarters. In addition, the S. dysgalactiae-infected quarters had higher percentages of milk T cells (CD3(+)) and their subset CD3(+)CD8(+)CD4(-) cells. Overall, the present study provided new insights into S. dysgalactiae IMIs, including distinct lymphocyte profiles, and a tendency toward an inhibition of apoptosis in milk neutrophils. (AU)

• FAPESP's process: 09/50672-0 - Functional evaluation of blood and milk leukocytes of cows naturally infected by bovine leukosis virus
• Grantee: Alice Maria Melville Paiva Della Libera
• Support Opportunities: Regular Research Grants