The effect of an immunomodulator (parapoxvirus ovis) on cell-mediated immunity (CMI) in abruptly weaned foals.

The research study investigates the effect of an immunomodulator (parapoxvirus ovis) on cell-mediated immunity responses in foals that have been abruptly weaned. The findings reveal a significant decrease in cytokine production regardless of the use of the immunomodulator, suggesting weaning significantly impacts a foal’s immunity and potentially increases its susceptibility to infections.

Objectives of the Research

• The primary objective of the research was to investigate the impact of parapoxvirus ovis (PPVO), an immunomodulator, on the cell-mediated immunity (CMI) responses of abruptly weaned foals. This focus comes from understanding the relationship that exists between the weaning process, which is stressful, and the increased risk of infectious disease in young horses.

Methodology

• Two groups of foals were selected for the study. The first group (6 foals) received an intramuscular injection of PPVO on specific days: two days before weaning, on the day of weaning, and nine days after weaning.
• The second group which served as the control group had five foals. They received only the diluent (a substance that dilutes something) on the same days as the first group.
• Blood was collected from all the foals before and after weaning on specific days, and whole blood samples were prepared to determine cytokine mRNA expression by reverse transcription and real-time PCR (RT-PCR).
• Peripheral blood mononuclear cells were isolated and stimulated to determine in vitro cytokine production. The cytokines analyzed were interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and interleukin-10 (IL-10).

Results and conclusion

• The study found that regardless of the PPVO treatment, foals that underwent the weaning process had a significant decrease in both in vivo and in vitro cytokine production. This reduction was observed in all cytokines: IFN-γ, TNF-α, and IL-10.
• The results thus suggest that abrupt weaning greatly impacts the cell-mediated immunity of the foal, which in turn could result in increased susceptibility to infections. This outcome implies that care should be taken to manage the weaning process to mitigate any negative effects on the immunity of young horses.