Eg95: A Vaccine against Cystic Echinococcosis

Abstract

Hydatidosis or cystic echinococcosis (CE) is caused by the larval stage of the tapeworm Echinococcus granulosus. This parasite is cosmopolitan in distribution and causes significant economic losses to the meat industry, mainly due to condemnation of edible offal. Echinococcosis treatment in human is very expensive as it requires extensive surgery or prolonged chemotherapy or use of both. In Asia and Africa, the vulnerable population of developing the disease is around 50 million. Office International des Epizooties (OIE) has recognized CE as a multi species disease. The parasite has acquired the capability to survive long time within the host due to a specific mechanism to evade the host immune system. A specific class of proteins known as secreted and membrane bound (S/M) proteins play key roles in the evasion mechanism. A total of 12 S/M proteins have been reported as immunodiagnostic and immunoprophylactic agents. Of these, Eg95 is a candidate antigen used for immunization of animals. Literature suggests that, Eg95 is a multi-gene family (Eg95-1 to Eg95-7) and exists in seven different isoforms. This chapter will describe minutely efficacy of Eg95 as a vaccine candidate based on animal trial and potentiality of other S/M proteins as immunodiagnostic antigen and immune evasion.