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Published on: July 6, 2014
Flow cytometric analysis: Interdependence of healthy and infected udder quarters
M G Blagitz1, F N Souza2, C F Batista1
1Departamento de Clínica Médica, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Av. Prof. Dr. Orlando Marques de Paiva, 87, Cidade Universitária, São Paulo 05508-270, Brazil.
Insights
Intramammary infections in dairy cows show quarter interdependence. An infected quarter influences immune cell markers in uninfected quarters, suggesting a systemic response to localized infection.
Area of Science:
- Veterinary Immunology
- Dairy Cattle Health
- Bovine Mastitis Research
Background:
- The independence versus interdependence of dairy cow udder quarters during intramammary infections remains a debated topic.
- Understanding inter-quarter communication is crucial for effective mastitis management and herd health.
Purpose of the Study:
- To investigate the immune status of uninfected quarters in udders with and without an infected quarter.
- To evaluate potential interdependence between udder quarters by analyzing milk neutrophil function and lymphocyte profiles.
Main Methods:
- Flow cytometry was used to analyze milk neutrophils (adhesion molecules, ROS, phagocytosis, viability) and lymphocyte subsets (B cells, T cell subsets).
- Uninfected quarters from uninfected udders (control) and uninfected quarters from udders with one infected quarter were compared.
Main Results:
- No significant differences were observed in somatic cell count or neutrophil percentages in neighboring uninfected quarters.
- Neutrophil viability, ROS production, and phagocytosis of Staphylococcus aureus were not affected by infection in adjacent quarters.
- However, expression of adhesion molecules (CD11b, CD62L, CD44) on milk neutrophils and the percentage of B cells were significantly higher in uninfected quarters from infected udders.
Conclusions:
- The study provides strong evidence for udder quarter interdependence in dairy cows.
- Localized intramammary infection impacts immune cell profiles in adjacent uninfected quarters, suggesting a coordinated immune response.
Abstract:
An important question about intramammary infections that is still debated in the literature is the independence or interdependence of the quarters of dairy cows. The present study sought to explore milk neutrophil function and the milk lymphocyte profile of uninfected quarters from uninfected and infected (one infected quarter per cow) udders to evaluate interdependence of the quarters. Thus, 32 (8 cows) and 18 (6 cows) uninfected quarters from uninfected and infected udders were used, respectively. Using flow cytometry, we evaluated the percentage of milk neutrophils and their expression of adhesion molecules L-selectin (CD62L), β2-integrin (CD11b), and an endothelial-selectin ligand (CD44); levels of intracellular reactive oxygen species (ROS); phagocytosis of Staphylococcus aureus by milk neutrophils; and neutrophil viability. Furthermore, we assessed the percentage of B-cell (CD21(+)) and T-lymphocyte subsets (CD3(+)/CD4(+)/CD8(-), CD3(+)/CD8(+)/CD4(-), CD3(+)/CD4(+)/CD25(-), CD3(+)/CD4(+)/CD25(+), and CD3(+)/CD4(-)/CD25(-)) using flow cytometry with monoclonal antibodies. The infected quarter did not affect somatic cell count or the percentage of neutrophils in the neighboring uninfected quarters. Furthermore, the infected quarter did not influence neutrophil viability, intracellular reactive oxygen species production, or phagocytosis of S. aureus by milk neutrophils. Conversely, the expression of adhesion molecules CD11b, CD62L, and CD44 by milk neutrophils differed between uninfected quarters from infected versus uninfected udders. The lymphocyte subsets did not differ between groups, except for a higher percentage of B cells in uninfected quarters from infected udders than in those from uninfected udders. Thus, our study strongly supports the hypothesis of interdependence of quarters based on the influence of infection on both the percentage of B cells and the expression of adhesion molecules by milk neutrophils in the neighboring uninfected quarters.
