Teimouri Aref, Abbaszadeh Afshar Mohammad Javad, Mohtasebi Sina, Jafarpour Azami Sanaz, Alimi Rasoul, Keshavarz Hossein
Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Department of Medical Parasitology and Mycology, Tehran University of Medical Sciences, Tehran, Iran.
J Clin Microbiol. 2021 Jul 19;59(8):e0041621. doi: 10.1128/JCM.00416-21.
To improve serodiagnostic methods for diagnosis of acute from chronic toxoplasmosis, an economical in-house enzyme-linked immunosorbent assay (ELISA) for measuring -specific IgG, IgM, and IgG avidity has been developed and assessed based on use of various Toxoplasma gondii antigens, including SAG1, GRA7, and a combination of SAG1 and GRA7 (SAG1+GRA7), as well as lysate antigens (TLAs). Performances of in-house IgM, IgG, and IgG avidity assays were compared to those of ELISA commercial kits and VIDAS Toxo IgG avidity. A set of 138 sera from patients with acquired T. gondii infection and seronegative people were assessed. Receiver operating characteristic (ROC) analysis revealed an area under curve (AUC) of 0.98, 0.97, 0.99, and 0.99 for IgM-TLAs, IgM-SAG1, IgM-GRA7, and IgM-SAG1+GRA7, respectively. Furthermore, AUC was calculated as 0.99, 0.99, 0.98, and 0.99 for IgG-TLAs, IgG-SAG1, IgG-GRA7, and IgG-SAG1+GRA7, respectively. The current study showed that GRA7 included 100% sensitivity for the detection of Toxo IgM, while SAG1 included 89.7% sensitivity. Furthermore, the highest specificity (97.2%) to detect Toxo IgM was achieved using SAG1+GRA7 antigen. For the detection of Toxo IgG, the highest sensitivity (100%) was recorded for SAG1+GRA7, followed by TLAs (97.9%). The SAG1+GRA7 showed the greatest potential for assessing avidity of IgG antibodies, with 97.1% sensitivity and 96.6% specificity compared to those of VIDAS Toxo IgG avidity. The preliminary results have promised better discriminations between acute and chronic infections using a combination of SAG1 and GRA7 recombinant antigens compared to those using TLAs.
为改进急性与慢性弓形虫病诊断的血清学诊断方法，基于使用多种刚地弓形虫抗原（包括SAG1、GRA7以及SAG1与GRA7的组合（SAG1+GRA7））以及裂解物抗原（TLA），开发并评估了一种用于检测特异性IgG、IgM和IgG亲和力的经济实用的内部酶联免疫吸附测定（ELISA）方法。将内部IgM、IgG和IgG亲和力测定的性能与ELISA商业试剂盒和VIDAS弓形虫IgG亲和力测定的性能进行了比较。对一组138份来自获得性弓形虫感染患者和血清阴性者的血清进行了评估。受试者工作特征（ROC）分析显示，IgM-TLA、IgM-SAG1、IgM-GRA7和IgM-SAG1+GRA7的曲线下面积（AUC）分别为0.98、0.97、0.99和0.99。此外，IgG-TLA、IgG-SAG1、IgG-GRA7和IgG-SAG1+GRA7的AUC分别计算为0.99、0.99、0.98和0.99。当前研究表明，GRA7对弓形虫IgM检测的敏感性为100%，而SAG1的敏感性为89.7%。此外，使用SAG1+GRA7抗原检测弓形虫IgM的特异性最高（97.2%）。对于弓形虫IgG的检测，SAG1+GRA7的敏感性最高（100%），其次是TLA（97.9%）。与VIDAS弓形虫IgG亲和力测定相比，SAG1+GRA7在评估IgG抗体亲和力方面显示出最大潜力，敏感性为97.1%，特异性为96.6%。初步结果表明与使用TLA相比，使用SAG1和GRA7重组抗原组合能更好地区分急性和慢性感染。
