Identification of novel antigens for serum IgG diagnosis of human toxoplasmosis

• Published in: Experimental parasitology 2019-09, Vol.204, p.107722-107722, Article 107722
• Main Authors: Luo, Juntao, Wan, Jingyi, Tang, Ziru, Shen, Shuang
• Format: Article
• Language: English
• Subjects: ELISA; GRA2; GRA7; Serodiagnosis; Toxoplasma gondii; TPI
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1016/j.exppara.2019.107722

In the present study, we attempted to identify antigens with high sensitivity and specificity for the serological diagnosis of human toxoplasmosis. We investigated soluble proteins from the tachyzoites of the RH strain of Toxoplasma gondii (T. gondii) and excreted/secreted antigens (ESAs) from the peritoneal protein of T. gondii-infected mice. One-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis revealed that in both soluble tachyzoite antigens and ESAs, the antigens located between 25 and 35 kDa had high diagnostic sensitivity. Further analysis of antigenic specificity revealed that the antigens located between 25 and 35 kDa were specifically recognized by the sera of toxoplasmosis patients, but other parasitic diseases were not. The protein spots between 25 and 35 kDa were selected after two-dimensional electrophoresis of both soluble tachyzoite antigens and ESAs. GRA2, GRA7, and triosephosphate isomerase (TPI) were successfully characterized from the protein spots using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectroscopy analysis. We expressed, purified, and evaluated proteins GRA2, GRA7, and TPI. TPI is a novel antigen with potential for the serological diagnosis of toxoplasmosis, and composite recombinant proteins (TPI, GRA2, and GRA7) have great sera diagnostic value for the detection of the disorder. [Display omitted] •TPI (triosephosphate isomerase) may be a novel antigen for serological diagnosis of toxoplasma gondii in human.•Composite recombinant proteins(TPI、GRA2 and GRA7) have high sensitivity and specificity for serological diagnosis of human toxoplasmosis.•The composite recombinant proteins(TPI、GRA2 and GRA7) might be a useful tool can accurately detect toxoplasmosis infection.