Age-related changes in lymphocyte subsets of quarter horse foals.

The research assessed how lymphocyte subsets (a type of white blood cell crucial to the immune system) in Quarter Horse foals vary from birth to 18 weeks of age, including individual differences, and evaluated the impact of overnight storage of blood samples.

Research Methodology

• Eight healthy Quarter Horse foals were used in this research. These foals were observed from birth till they reached 18 weeks of age.
• Blood samples were collected at various points within this duration and a complete blood count (CBC) was performed on each sample.
• To trace the presence of lymphocytes, the blood samples were stained for lymphocyte markers. This was done both immediately and after storing the samples overnight.
• The lymphocyte subset concentrations were then analyzed using a technique known as flow cytometry which is used to measure characteristics of cell populations.

Research Findings

• The total count of white blood cells (leukocytes), lymphocytes, and different subsets of lymphocytes were found to increase significantly with age.
• It was noted that the proportions of certain types of lymphocytes (B29A+, CD21+, and equine major histocompatibility complex class-II molecule+) also increased significantly with age.
• However, some lymphocyte proportions (Eq CD5+, EqCD8+, and EqWC4+) were found to decrease significantly over the same time period.
• Significant differences were found among the foals in terms of initial concentrations of the lymphocyte subsets, but the rate of increase was roughly the same for all foals. This suggested individual differences among the foals.
• No notable differences were found between subset values when comparing blood samples stained on the day of collection or after overnight storage at room temperature (approximately 21 C) or under refrigeration.

Conclusions

• The results confirmed an increase in lymphocyte subset numbers and proportions over time. However, the fact that there were individual differences among the foals was also established.
• These individual differences could imply varying susceptibility to infections among foals during the perinatal period.
• Furthermore, the fact that the overnight storage of blood samples doesn’t impact the subsequent measurements makes it possible for these measurements to be taken in the field, making such studies more feasible.