Influence of age on neutrophil function in foals.

This research investigates how the functional activities of neutrophil leucocytes (NL) and the concentrations of immunoglobulin G change as foals age from birth to 6 months old. The study found that the ability of NL to kill pathogens decreased and the ability to phagocytize increased until about 113 days old, then these trends began to reverse.

Study Design and Methods

• The researchers tested the phagocytosis (the process by which cells engulf particles) and killing capacity (the ability to destroy pathogens) of NL in six healthy foals from birth until they were 6 months old. NL from peripheral blood were reacted with the bacterium Streptococcus equisimilis in a medium containing 20 per cent pooled equine serum.
• The responses of the NL were observed at three different intervals: 30 minutes, 60 minutes, and 90 minutes. The measurement of these functional activities was determined using a fluorochrome microassay, a technique that uses fluorescence to quantify the biological activity of cells.

Results and Interpretation

• It was discovered that as foals aged, the killing capacity of their NL decreased while their phagocytic capacity increased. These trends continued till the foals reached 113 days after which the patterns began to reverse.
• Changes in Immunoglobulin G concentrations were also noted over time. Immunoglobulin G, an important type of antibody, showed the lowest levels between 29 to 56 days of age. Antibodies like Immunoglobulin G play a crucial role in fighting off infections and maintaining the immune response of an organism.
• Interestingly, despite these changes, all foal values for NL function fell within the range of normal values established for adult horses. This suggests that these changes are a normal part of the maturation process and do not indicate any dysfunction or disease state.

Significance and Outlook

• The findings of the study provide valuable insights into the development and maturation of the immune system in foals. This is important for understanding the health and disease prevention strategies in young horses.
• Further research on larger samples and on different species of horses could help to refine and expand our understanding of these developmental changes in horse immunity.