Toxoplasma Gondii: A Review of Excretory Secretory Antigens

Toxoplasma gondii is an obligatory intracellular protozoan that infects all warm-blooded vertebrates. Almost one-third of people throughout the world are infected by this parasite. Although toxoplasmosis is often lethal in HIV/AIDS patients، neoplastic disease، bone marrow or heart transplant recipients، it results in life-long protective immunity in healthy people. Hence، different antigens of T. gondii such as membrane، cytoplasmic and excreted-secreted antigens (ESA) can be potential candidates for immunization. Among these antigens، ESAs play an important role in induction of immune system responses. Dense granules، micronemes and rhoptries are secretory organelles in Apicomplexa protozoa. The contents of T. gondii are factors of recognition and attachment to cells، making parasitophorous vacuole (PV)، and intracellular proliferation and survival، and pathogenesis. This article reviews different kinds of ESA released from these structures. It seems necessary to identify molecular aspects of ESA before diagnosis، treatment and immunization studies.