Neutrophil function of neonatal foals is enhanced in vitro by CpG oligodeoxynucleotide stimulation.

The research article investigates if stimulating neutrophils, a type of innate immune cell, from young horses (foals) with a TLR9 agonist called CpG 2142 increases their ability to fight Rhodococcus equi, a bacterium that causes pneumonia in horses. The research also studies if this stimulation is effective at different stages of a foal’s life.

Objective and Method of Study

• The aim of the study was to verify whether the neutrophils from neonatal foals would respond favorably to in vitro stimulation with the TLR9 agonist CpG 2142 and how it would affect their function at varying ages (2, 14, and 56 days) to fight against Rhodococcus equi infection.
• In the experiment, researchers examined the degranulation (a process where cells release antimicrobial cytotoxic molecules) and gene expressions of cytokines and TLR9 (part of the immune system that recognizes foreign substances) in neutrophils after treatment with CpG 2142.

Results and Findings

• According to the findings, neutrophil degranulation was notably enhanced when stimulated with CpG alone, R. equi alone or in combination with either R. equi or another compound, N-formyl-methionyl-leucyl-phenylalanine (fMLP). However, this enhancement was not observed when neutrophils were stimulated with fMLP alone.
• There weren’t significant differences in CpG-induced cytokine expression across different ages. However, more expression of IL-12p40 cytokine was observed on day 56 as compared to days 2 or 14.
• When the data were compiled across all ages, it was observed that CpG 2142 significantly increased the mRNA expression of cytokines IL-6 and IL-17.

Conclusion

• From the experiment, the researchers concluded that in vitro stimulation of neutrophils from foals with CpG 2142 enhances their function by promoting degranulation and inducing mRNA expression of cytokines IL-6 and IL-17, and this holds true regardless of the age of the foal.
• This could mean that CpG 2142 can be used to bolster the immune response in foals against Rhodococcus equi infection, potentially reducing the incidence of pneumonia in young horses.