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Abstract：
To improve serodiagnostic methods for diagnosis of acute from chronic toxoplasmosis, an economical in-house enzyme-linked immunosorbent assay (ELISA) for measuring Toxoplasma-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 Toxoplasma 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.
摘要：
改善血清诊断方法，以诊断急性弓形虫病。一种经济的内部酶联免疫吸附测定（ELISA），用于测量弓形虫特异性IgG，IgM,和IgG亲和力已经开发和评估基于使用各种弓形虫抗原，包括SAG1，GRA7，以及SAG1和GRA7的组合（SAG1+GRA7），以及弓形虫裂解物抗原（TLAs）。内部IgM的表现，IgG,将和IgG亲合力测定与ELISA商业试剂盒和VIDASToxoIgG亲合力测定进行比较。对获得性弓形虫感染和血清阴性患者的138份血清进行了评估。接收器工作特征（ROC）分析显示，IgM-TLA的曲线下面积（AUC）为0.98、0.97、0.99和0.99，分别为IgM-SAG1、IgM-GRA7和IgM-SAG1+GRA7。此外，IgG-TLAs的AUC计算为0.99、0.99、0.98和0.99，IgG-SAG1、IgG-GRA7和IgG-SAG1+GRA7。目前的研究表明，GRA7对检测ToxoIgM的灵敏度为100％，而SAG1包括89.7%的敏感性。此外，使用SAG1+GRA7抗原检测ToxoIgM的特异性最高(97.2%).用于检测ToxoIgG，SAG1+GRA7的灵敏度最高(100%),其次是TLA(97.9%).SAG1+GRA7显示出评估IgG抗体亲和力的最大潜力，与VIDASToxoIgG亲和力相比，灵敏度为97.1％，特异性为96.6％。与使用TLA的组合相比，初步结果有望更好地区分使用SAG1和GRA7重组抗原的急性和慢性感染。
