Cloning and expression of recombinant equine interleukin-3 and its effect on sulfidoleukotriene and cytokine production by equine peripheral blood leukocytes.

This study successfully cloned and expressed the equine Interleukin-3 (IL-3) gene, a growth factor for hematopoietic cells. The produced recombinant equine IL-3 was found to influence leukotriene and cytokine production in equine blood cells, and particularly increased certain responses in horses affected by insect bite hypersensitivity (IBH).

About the Research

• Interleukin-3 (IL-3), a factor involved in the growth and differentiation of a number of blood cells, had not previously been studied in horses due to a lack of horse-specific reagents for testing.
• The researchers’ objective was to clone and express the equine IL-3 and test its effect on the production of sulfidoleukotriene (sLT) and cytokines by equine peripheral blood leukocytes (PBL) – white blood cells that circulate in the blood vessels.
• The study involved the cells of both healthy horses and horses affected by insect bite hypersensitivity (IBH), a common allergic skin condition in horses.

Findings

• The team successfully cloned and expressed the equine IL-3 gene in E. coli, and purified it for testing.
• IL-3 had a dose-dependent effect on sLT production by the stimulated equine PBL, including increasing IL-4, IL-13 and thymic stromal lymphopoietin (TSLP) expression, relative to non-primed cells.
• The effects of IL-3 were particularly notable on the Culicoides-induced sLT responses of horses affected by IBH, but not in healthy horses. Younger IBH-affected horses were particularly influenced by this.

Implications

• The production of a functional equine IL-3 will not only facilitate further immunological studies in horses but also improve the sensitivity of diagnostic tests for allergies.
• This breakthrough will increase our understanding of the immune responses in horses and could potentially lead to more effective therapeutic strategies for conditions such as IBH.