Simple and Efficient Method for Measuring Anti-Toxoplasma Immunoglobulin Antibodies in Human Sera Using Complement-Mediated Lysis of Transgenic Tachyzoites Expressing β-Galactosidase

A simple and efficient method using transgenic Toxoplasma gondii tachyzoites expressing β-galactosidase was developed for detection of specific antibodies against the parasite in sera of patients. The titers obtained with the new test were similar to those obtained with the Sabin-Feldman dye test run in parallel. Although significant changes in endpoint titers were not observed when sera drawn sequentially at 2- to 3-week intervals were tested with both procedures, apparent differences in antibody affinity were observed with the new test which were not perceptible with the Sabin-Feldman dye test. Like the Sabin-Feldman dye test, the new test is based on complement lysis of tachyzoites, but it is much easier to perform and the reaction is read colorimetrically instead of visually.

本研究研发出一种简便高效的检测方法，通过表达β-半乳糖苷酶（β-galactosidase）的转基因弓形虫（Toxoplasma gondii）速殖子（tachyzoites），用于检测患者血清中针对该寄生虫的特异性抗体。该新检测方法所得抗体效价与平行开展的萨宾-费尔德曼染色试验（Sabin-Feldman dye test）结果相近。尽管以2至3周间隔连续采集的血清经两种方法检测后，其终点效价未出现显著变化，但新检测方法可观测到抗体亲和力的明显差异，而萨宾-费尔德曼染色试验无法检测到这类差异。与萨宾-费尔德曼染色试验类似，新检测方法同样基于速殖子的补体裂解反应，但操作更为简便，且反应结果通过比色法读取，而非目视判断。