Evaluation of Recombinant SRS3 Antigen for Diagnosis of Toxoplasmosis by Enzyme-Linked Immunosorbent Assay

Background: Infections by the protozoan parasite Toxoplasma gondii (T. gondii) are widely prevalent in human and animals. SRS3 is a member of SRS antigen family (glycosylphosphatidylinositol-linked proteins), which is structurally related to the highly immunogenic surface antigen SAG1. The SAG family of proteins can cover the surface of T. gondii bradyzoites and tachyzoites.Objectives: The aim of this study was to evaluate the recombinant SRS3 protein for diagnosis of toxoplasmosis by enzyme-linked immunosorbent assay.Methods: Indirect immunoglobulin G (IgG) enzyme-linked immunosorbent assays (ELISAs) with recombinant SRS3 and SAG1 proteins of T. gondii were developed to evaluate the diagnosis of infection in pregnant women.Results: The results showed that sensitivity and specificity were respectively 84.12% and 92% for recombinant protein SRS3 and 92% and 96% for rSAG1.Conclusions: Recombinant proteins SRS3 and rSAG1 are promising antigens in diagnostic assays for detection of specific antibodies against T. gondii.