Possible Correlation between Helminths and Immune System; Immunogenic Antigens of T. Spiralis

Abstract

Human trichinellosis is one of the most common parasitic zoonosis worldwide caused by nematodes infection of genus Trichinella. Human infections occur after consumption of raw or undercooked meat containing encysted larvae.  Pigs are a major source of infection in humans. T. spiralis adult is one of the smallest nematodes infecting man and is white in color. Humans have established an immunological balance between the TH1/TH17 and TH2 responses, of which the TH1/TH17 response is mostly related to autoimmunity while the TH2 response is related to parasite infections. T. spiralis has the unique capacity to make itself "at home" by hiding in the host body in a new type of cell called the “nurse cell”. From this immunologically privileged location, the parasite organizes a long-lasting molecular cross-interaction with the host via excretory–secretory (ES) antigens. They have a variety of effects as they can diminish inflammation caused by muscle cell invasion and regulate immunological responses in a way to be protective for both the host and the parasite. T. spiralis is a parasite that causes a long-term infection in the host's skeletal muscles. The parasite could survive until the end of life (in rats) and for several months to years after infection in higher species or humans. Unlike some other internal parasites, it does not damage the host's muscle cells, making it one of the most successful parasitic symbiotes. In human trichinellosis, the innate and adaptive immune responses of the host are activated to resist the invasion of parasites, and undergo the process of elimination. Establishment of T. spiralis infection requires modulation of the host's immune response in order to escape their own expulsion, but it must be carefully regulated to avoid threatening host survival.