Administration of Porcine Interleukin-3 Induces Increased Levels of Blood Eosinophils

Increasing resistance to anthelmintic drugs indicates a vital need to develop alternative strategies to control helminth infections. Interleukin-3 (IL-3) is a multilineage hematopoietic growth regulator produced by activated T lymphocytes in response to infection. In helminth infections, eosinophils play an important role in the elimination of parasites through their recruitment of inflammatory cells and the release of granules. The ability of IL-3 to stimulate the development of eosinophils makes it a particularly important candidate for therapeutic use to protect against parasites. To enable the role of IL-3 in the development, growth, and differentiation of porcine eosinophils to be elucidated, recombinant IL-3 (rPoIL-3) was expressed and purified. As the amino acid sequence identities between porcine IL-3 and other reported species were quite low (∼39% between human and pig), an assessment of the in vitro activity of rPoIL-3 was made. The culture of porcine bone marrow (BM) cells with rPoIL-3 stimulat...