Effects of a P-class CpG-ODN administered by intramuscular injection on plasma cytokines and on white blood cells of healthy horses.

This research focused on understanding the effects of a P-class Cytosine-phosphate-guanosine (CpG-ODN) when administered through an intramuscular injection on the white blood cells and plasma cytokines of healthy horses. The study found that the injection was well-tolerated with minor side effects and resulted in changes in the distribution of white blood cells, but no changes were reported in plasma cytokines.

Research Objective

• The primary goal of this study was to expand the understanding of how a P-class CpG-ODN, when administered systemically and intramuscularly, affects hematology, specifically the distribution of white blood cells, and plasma cytokines (IFN-α, IL-10, TNF-α, IFN-γ) in healthy horses.

Methodology

• Eight healthy horses were selected for this study.
• Each received intramuscular injections of either CpG-ODN or a placebo (PBS) twice, with a seven-day interval between injections.
• Following a two-month washout period, the groups were reversed.
• A complete physical examination, complete blood count (CBC), and plasma cytokine measurements were carried out from two days before each injection until 21 days post-injection.

Findings

• The P-class CpG-ODN injection was generally well-tolerated, producing only minor side effects.
• The study reported significant temporary decreases in total circulating leukocytes, lymphocytes, and eosinophils, while monocytes experienced a temporary increase following each injection.
• The P-class CpG-ODN did not produce severe side effects at a dose of 5mg in seven out of the eight horses. One horse did exhibit temporary pyrexia (fever).
• There was a noted redistribution of white blood cells in horses that received the CpG injections. However, the study found no changes in plasma cytokines at the tested dosage, route of administration, and sampling times.