Alterations of serum tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and sialic acids in malignant ovine theileriosis

Abstract

The study was designed to evaluate the effect of the severity of Theileria lestoquardi (hirci) infection on tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and sialic acid concentration in blood sera in a naturally infected sheep. Infected animals (diseased group) comprised 50 Iranian fat-tailed sheep, about 1–2 years old, naturally infected with Theileria lestoquardi (hirci), were divided into three subgroups according to parasitemia rates ( 4%). As a control group, ten noninfected sheep were also selected. Hematological parameters and levels of TNF-α, IFN-γ, and sialic acid (TSA, LBSA, and PBSA) concentrations were measured in both groups. The results showed significant increases in the level of TNF-α, IFN-γ, and sialic acid concentrations in infected sheep compared with noninfected ones (P < 0.05). The increased level of TNF-α and IFN-γ in infected sheep may indicate the role of these cytokines to inhibit the growth and development of the parasite in infected host cells. Also, it is speculated that preventing the establishment of parasites by inhibiting the differentiation of trophozoites to schizonts is another aspect of the enhanced activity of these substances. In addition, increased levels of sialic acid concentration during parasitemia presumably stimulate the host immune response and influence the parasite–host cell adhesion. Clearly, further molecular and biochemical investigations are needed to elucidate the exact mechanisms involved in immunopathogenesis of malignant ovine theileriosis.