Impact of Sarcocystis fusiformis Crude Antigen Administration on Innate and Adaptive Immune Responses of Wistar Rats

Abstract

Background: Sarcocystis fusiformis is an apicomplexan intracellular protozoan parasite that infects Indian water buffalo, Bubalus bubalis, in Egypt. Aim of the Work:The purpose of the study was to assess the changes in the immune parameters of male Wistar rats following their oral administration with thermally treated or fresh extract of Sarcocystis. Materials and Methods: Sarcocysts were isolated from the esophageal muscle specimens that were collected from the slaughtered Indian water buffaloes. These cysts were morphologically described by light microscopy and transmission electron microscopy. Rats (18 per group) were orally administered with; saline (control group), thermally treated cyst extract (heated group) or fresh cyst extract (fresh group). The serum levels of interleukin (IL)-1β, IL-18, IL-15, tumor necrosis factor (TNF)-α, IL-12, IL-10, and IL-13 were measured on days 7, 14, and 28 post-administration. Cells positive for CD4, CD8, IgG, and the phosphorylated-NF-κB have been detected by the immunohistochemical technique at the end of the study. Results: In both thymus and spleen, the area%, as well as the number of CD4+ and CD8+ T cells in response to the fresh extract were significantly increased compared to the control group. On day 28, the fresh extract induced a significant increase in the levels of IL-1β, IL-18, IL-15, IL-12, IL-10, and IL-13 while thermally treated extract was significantly elicited higher levels of IL-15, IL-12, and IL-13 in comparison to the control group. The number of positive splenocytes for phosphorylated-NF-κB was significantly higher in the fresh group than in the heated or control group. In response to fresh extract, the number of IgG+ cells was markedly increased in the follicular zone of the lymph node in comparison with controls. Conclusion:The state at which the parasite extract was administered (fresh or thermally treated cysts) has an inherent influence on immune responses, both innate and adaptive.