Tsang V C, Tao Y, Qui L, Xue H
J Parasitol. 1982 Dec;68(6):1034-43.
To identify sources of high potency antigens for use in serodiagnosis, aqueous-soluble egg antigens from Schistosoma japonicum were extracted with Dulbecco's phosphate-buffered saline. Residual particulates were solubilized with Tris-buffered 8 M urea, yielding a urea-soluble egg antigen fraction. The urea-soluble fraction was further fractionated with Bio Gel A50m and QAE-Sephadex. All fractions were quantitatively assayed for their specific antigenic activities against serum specimens from infected rabbits by the single-tube enzyme-linked immunosorbent assay (k-ELISA). In antigen rate-limiting conditions, the urea-soluble particulate fractions were more antigenically active than the aqueous-soluble fraction. In antigen-excess and antibody-limiting assay conditions, the ideal conditions for serologic assays, the urea-derived antigens also showed superior activities against sera from infected humans. Analysis by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) on gradient gels revealed numerous low molecular weight protein bands in the aqueous-soluble fraction, whereas the urea-soluble fractions appeared to be much simpler with the majority of their proteins concentrated in one or two high molecular weight bands (greater than or equal to 200 kdaltons). Electro-transfer blots of the SDS-PAGE onto nitrocellulose papers and subsequent visualization of antigens by enzyme-linked immunoabsorbence confirmed these findings. The above data suggest that the urea-soluble fraction of S. japonicum eggs is antigenically active and has potential use in the development of a diagnostic reagent.
为了鉴定用于血清学诊断的高效抗原来源，用杜尔贝科磷酸盐缓冲盐水提取日本血吸虫的水溶性虫卵抗原。残留颗粒用三羟甲基氨基甲烷缓冲的8M尿素溶解，得到尿素溶性虫卵抗原部分。尿素溶性部分再用生物凝胶A50m和QAE-葡聚糖进行分级分离。通过单管酶联免疫吸附测定法（k-ELISA）对所有部分针对感染兔血清标本的特异性抗原活性进行定量测定。在抗原限速条件下，尿素溶性颗粒部分比水溶性部分具有更高的抗原活性。在抗原过量和抗体限量的测定条件下，即血清学测定的理想条件下，尿素衍生抗原对感染人类血清也显示出优越的活性。在梯度凝胶上进行的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析显示，水溶性部分有许多低分子量蛋白条带，而尿素溶性部分似乎要简单得多，其大部分蛋白质集中在一两个高分子量条带（大于或等于200千道尔顿）中。将SDS-PAGE的电转移印迹到硝酸纤维素纸上，随后通过酶联免疫吸附法对抗原进行可视化，证实了这些发现。上述数据表明，日本血吸虫虫卵的尿素溶性部分具有抗原活性，在诊断试剂的开发中具有潜在用途。
