Intramuscular administration of a synthetic CpG-oligodeoxynucleotide modulates functional responses of neutrophils of neonatal foals.
Authors: Cohen Noah D, Bourquin Jessica R, Bordin Angela I, Kuskie Kyle R, Brake Courtney N, Weaver Kaytee B, Liu Mei, Felippe M Julia B, Kogut Michael H
Journal: PloS one
Summary
Neonatal foals are notably susceptible to infection due to immature neutrophil function, prompting investigation into whether intramuscular administration of a CpG-oligodeoxynucleotide (CpG-ODN) immunostimulant could enhance their innate immune responses during a critical developmental window. Eighteen foals received either CpG-ODN formulated with Emulsigen or saline injections on days 1 and 7 of life, with neutrophil function assessed at multiple timepoints through day 28 using mRNA expression analysis, degranulation assays, and reactive oxygen species measurement. Treatment significantly elevated interferon-gamma (IFN-γ) expression—a key Th1 cytokine—on days 3, 9, and 14, whilst degranulation was reduced at days 3 and 14 compared to controls, suggesting a more controlled inflammatory response rather than excessive neutrophil activation. The lack of effect on reactive oxygen species production indicates the CpG-ODN modulates cytokine-mediated immunity without stimulating oxidative bursts, which may reduce tissue damage whilst maintaining antimicrobial capacity. These findings suggest potential clinical applications for foals at high risk of neonatal sepsis or those with failure of passive transfer, though further investigation into optimal dosing, timing relative to infectious challenge, and integration with existing vaccination protocols would be necessary before routine implementation in practice.
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Practical Takeaways
- •Early immunomodulation with CpG-ODN shows promise as a strategy to boost immune function in vulnerable neonatal foals and potentially reduce infection risk
- •Treatment timing matters: administering the formulation at days 1 and 7 produced sustained improvements in key immune markers through day 14
- •This approach may enhance vaccine responses in foals, though clinical efficacy against actual disease has not yet been demonstrated in this study
Key Findings
- •Intramuscular CpG-ODN administration on days 1 and 7 significantly increased interferon-γ mRNA expression in foal neutrophils on days 3, 9, and 14 (P<0.05)
- •Degranulation was significantly reduced in CpG-ODN-treated foals compared to controls at days 3 and 14 (P<0.05)
- •No significant effect of CpG-ODN treatment on reactive oxygen species generation was detected
- •CpG-ODN formulation may enhance both innate and adaptive immune responses in neonatal foals