Toxoplasma gondii Recombinant Antigens as Tools for Serodiagnosis of Human Toxoplasmosis: Current Status of Studies

Abstract

Toxoplasma gondii is a parasitic protozoan which is the cause of toxoplasmosis. Although human toxoplasmosis in healthy adults is usually asymptomatic, serious disease can occur in the case of congenital infections and immunocompromised individuals. Furthermore, despite the exact recognition of its etiology, it still presents a diagnostic problem. Diagnosis of toxoplasmosis is mainly based on the results of serological tests detecting anti-T. gondii-specific antibodies in the patient's serum sample. The specificities and sensitivities of serology tests depend mostly on the diagnostic antigen(s) used. Most of the commercial serological kits currently available are based on Toxoplasma lysate antigens (TLAs). In recent years, many studies showed that recombinant antigenic proteins of T. gondii may be an alternative source of antigens which are very useful for the serodiagnosis of toxoplasmosis. This article presents a review of current studies on the application and usefulness of different T. gondii recombinant antigens in serological tests for the diagnosis of human toxoplasmosis.

Effective Diagnostic Marker for Serodiagnosis of Toxoplasma gondii Infection: New Developments and Perspectives

“…A significant variation between laboratories exists in the process of producing native antigen. Furthermore, antigen contamination with non-parasitic materials is also possible because of the lack of standard method for antigen purification [32]. Moreover, the use of live pathogens in antigen preparation process needs extra care because of biological hazards generated by the parasite [33].…”

“…Moreover, the use of live pathogens in antigen preparation process needs extra care because of biological hazards generated by the parasite [33]. Therefore, serological tests that use tachyzoite crude antigens seem difficult to standardize [32]. To overcome this limitation and improve the serodiagnostic tests, recombinant antigen may be used as an alternative diagnostic marker, and it could replace the native antigens [34].…”

“…Interestingly, one of the most advantageous of using recombinant antigen in the development of diagnostic tests is that the potential to determine precise protein composition, with reduced non-parasitic material. In addition, more than one antigen can be combined in a single test [32].…”

“…Most previous and current studies approved that recombinant protein technology significantly improves the serodiagnosis of T. gondii infection. Moreover, the uses of recombinant antigen allow not only the detection of anti-T. gondii antibodies but also differentiation between recently acquired and previous infections, resulting in reduced medical complication risk of the disease in immunocompromised patients, especially pregnant women [32]. The potential ability of specific T. gondii recombinant antigen to identify the clinical phases of the disease was extensively studied, in the attempts to discriminate acute from chronic infection.…”

Toxoplasmosis and Public Health Genomics

“…The serologic screening of IgM, IgA, and IgG is important to determine current or past infections of the pregnant women [88,93]. In addition to serological methods, ELISA IgG avidity is also found safe, efficient, and easy to determine T. gondii infection in the first trimester of pregnancy in routine diagnostic treatment [94,95]. PCR is an effective diagnostic tool to determine the pathogen in a tiny amount of sample with high specificity [96][97][98].…”