Peripheral blood neutrophil function and lymphocyte subpopulations in cycling mares.

The research article focuses on studying the immunity parameters in mares during their oestrus cycle. The study does not find significant changes in these parameters between the different phases of the oestrus cycle, suggesting that these phases may not influence the mare’s immune status.

Objective and Methodology

• The research aimed to investigate the different aspects of immune health during the follicular and luteal phases of the oestrus cycle in mares through two consecutive years.
• The scientists analyzed the functional competence of peripheral blood neutrophils (a type of white blood cell) by assessing factors like chemotaxis (chemical activity that prompts cellular movement), phagocytosis (ability of cells to devour harmful particles), and oxidative burst (rapid release of reactive oxygen species) under regular cyclic conditions.
• In the second year, along with the analysis of peripheral blood neutrophil phagocytosis and oxidative burst, the team characterized the circulating lymphocyte subsets which are another type of white blood cells.
• The reproductive condition of 17 adult mares was assessed using ultrasonography, and the results were further backed by testing plasma progesterone levels.
• Chemotaxis tests were done using porous membranes placed in transwell chambers. The migratory behavior of cells was encouraged using Escherichia coli and N-formyl-Met-Leu-Phe as chemoattractants.
• The measurement of phagocytosis and oxidative burst in blood neutrophils was performed through flow cytometry with commercially available kits.
• T-lymphocyte subsets were analyzed by indirect immunofluorescence staining after incubation with antibodies meant specifically for CD2, CD3, CD4, and CD8 cell markers. Natural killer cells and B cells were estimated mathematically.

Findings

• No significant difference was noticed in migration, phagocytosis, and oxidative burst in either of the oestrous cycle stages.
• The statistical analysis of total white blood cell count also did not show a significant variance between different phases of the oestrous cycle. However, there was a minor trend noticed for blood neutrophils to increase under the effect of progesterone (a hormone primarily associated with menstrual and pregnancy-related changes).
• Lymphocytic subpopulations stayed consistent throughout the oestrous cycle, further affirming the initial findings.

Conclusion

• The research found that the immunity parameters, as studied during the luteal and follicular phases of the oestrus cycle, may not influence the immune status of a mare.
• This means the immune response and the ability of the mare’s system to fight off intruders remain consistent irrelevant of the phase in the oestrous cycle.
• However, the study also infers the potential role of progesterone, which requires further research to establish any causality between progesterone levels and blood neutrophils count.