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Effect of Prototheca zopfii on neutrophil function from bovine milk
Luciane T Cunha1, Silvana P Pugine, Claudia R Valle
1Departament of Basic Science, Faculty of Zootechny and Food Engineering-FZEA, Universidade de São Paulo, Av Duque de Caxias Norte, 225, 13635-000, Pirassununga, SP, Brazil.
Abstract:
This study was carried to investigate neutrophil function in the presence of Prototheca zopfii. For this purpose, bovine milk neutrophils were incubated in the absence (control) of and presence of P. zopfii, and then they were examined hydrogen peroxide (H(2)O(2)) production, antioxidant enzyme activities, and phagocytic capacity. Milk was collected from negative "California Mastitis Test" (CMT) quarter from three lactating Holstein cows after induction of leukocytosis with an intramammary infusion of oyster glycogen. H(2)O(2) production was measured using the phenol red method. Catalase activity was measured following H(2)O(2) reduction at 240 nm and the activity of glutathione reductase was determined by measuring the rate of NADPH oxidation at 340 nm. P. zopfii death was assessed by fluorescent microscopy using acridine orange assay and by colony forming units (CFUs). Comparisons between the groups were initially performed by analysis of variance (ANOVA). Significant differences were then compared using Tukey's test with a significance coefficient of 0.05. Hydrogen peroxide production, catalase and glutathione reductase activities by neutrophils incubated in presence of P. zopfii were stimulated five times, 21% and 27% respectively, compared to the unstimulated-neutrophils. Neutrophils did not affect P. zopfii death as shown by microscopy and CFUs. These observations led to the conclusion that the P. zopfii promote a high increase of H(2)O(2) production by neutrophils from bovine milk during algae exposition accompanied by increase of antioxidant enzyme activities; however, this process did not affect P. zopfii death.
Insights
Prototheca zopfii exposure stimulates bovine milk neutrophils to increase hydrogen peroxide (H2O2) production and antioxidant enzyme activity. However, these neutrophils do not effectively clear P. zopfii.
Area of Science:
- Veterinary Immunology
- Microbiology
- Bovine Health
Background:
- Prototheca zopfii is an alga that can cause mastitis in cattle.
- Neutrophils are key immune cells involved in combating infections.
- Understanding neutrophil function during P. zopfii infection is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the effect of Prototheca zopfii on bovine milk neutrophil function.
- To assess hydrogen peroxide production, antioxidant enzyme activities, and phagocytic capacity of neutrophils in the presence of P. zopfii.
Main Methods:
- Bovine milk neutrophils were isolated from healthy Holstein cows.
- Neutrophils were incubated with or without P. zopfii.
- Hydrogen peroxide production was measured using the phenol red method.
- Catalase and glutathione reductase activities were quantified.
- P. zopfii viability was assessed using acridine orange staining and colony-forming units (CFUs).
Main Results:
- Neutrophils incubated with P. zopfii showed a five-fold increase in hydrogen peroxide production.
- Catalase and glutathione reductase activities increased by 21% and 27%, respectively.
- Neutrophils did not significantly reduce P. zopfii viability.
Conclusions:
- Prototheca zopfii exposure significantly enhances bovine milk neutrophil's oxidative burst and antioxidant enzyme activity.
- Despite increased neutrophil activity, P. zopfii is not effectively cleared, suggesting immune evasion strategies by the alga.
