Effect of Fasciola hepatica proteins on the functioning of rat hepatocytes

Fasciolosis is a hepatic parasitic infection that affects many mammal species and creates a great economic and veterinary problem. Molecular mechanisms of parasite–hepatocyte interactions have not been precisely characterized yet. Therefore, the aim of the study was to investigate alterations in the metabolic activity of rat liver cells exposed to Fasciola hepatica somatic proteins. Hepatocytes were incubated with 0–1 mg/ml of fluke's somatic proteins for various periods of time. Afterward, changes in hepatocytes metabolic activity were determined with MTT and enzyme leakage tests. Hepatocytes' capacity to synthesize albumin was also investigated. It was observed that protein concentration, as well as longevity of their action, influenced metabolic activity of rat liver cells. Diminution of hepatocytes survival rate, an increase in enzyme leakage and altered synthetic capacity after treatment with parasite's proteins were reported. It is concluded that somatic proteins of F. hepatica may play an important role in liver cell damaging

Evasion of host immunity by parasites

Protozoa and helminth parasites infect billions people and domestic animals all over the world. The infections are usually long-lasting because parasites have developed very efficient strategies of evasion of host innate and adaptive immunity defenses. Intracellular protozoa can remodel the phagosomal compartments and disturb the signalling pathways of the host macrophages, therefore they can avoid being killed by lysosomal enzymes and toxic metabolites of the host. Extracellular parasites developed the ability to avoid complement lysis and antibody dependent cell cytotoxicity. In addition, both protozoan and helminth parasites manage to modify the antigen-presenting and immunoregulatory functions of dendritic cells and T lymphocytes. Due to excretion of immunoinhibiting substances and modulators of host cytokines the parasites may suppress both the Th1 (cell-mediated immunity) and Th2 (humoral immunity) responses. Recently, it has appeared that both protozoan and helminth parasites demonstrate the ability either to prevent or promote apoptosis of host cells according to their own advantage