Production of MAG1 Antigen of Toxoplasma gondii in Escherichia coli

Toxoplasma gondii is an obligate intracellular protozoan parasite that can infect human and other warm-blooded animals. Although usually asymptomatic in immunocompetent individuals, toxoplasmosis may reactivate in immunocompromised patients (e.g. AIDS patients and organ transplant recipients) and cause severe diseases such as toxoplasmic encephalitis. Moreover, primary maternal infection can put the fetus at risk for serious medical problems, e.g., permanent neurological and ocular damage or even for death in utero. On the other hand, occurrence of T. gondii infection before pregnancy brings no danger to the fetus, except in immunocompromised mothers [1]. Laboratory diagnosis of the infection mainly relies on detection of specific anti-T. gondii antibodies, most commonly IgG and IgM antibodies, by a variety of serologic tests [2, 3]. The current methods for discrimination of acute from chronic infections, i.e., IgM and IgG avidity serologic tests, have their own limitations, e.g., low specificities and high amounts of false-positive or indeterminate results [4-7]. Several studies showed antibody response to some antigens of T. gondii including GRA2 [8], GRA6 [9], GRA7 [10], GRA8 [11], and response to MAG1 [12, 13] was stronger or much stronger during acute infection. Application of these antigens in serological tests might be useful, along with other tests, in distinguishing between acute and chronic infections.