Giannini S H, D'Alesandro P A
J Parasitol. 1982 Oct;68(5):765-73.
Host IgG is a component of the surface coat of Trypanosoma lewisi; it is specifically acquired during infection in the rat, concomitant with a rise in titer of trypanostatic (ablastic) activity of host serum. Host IgG was eluted from trypomastigotes at 7 to 9 days postinfection with a high salt-low pH buffer. Surface coats and trypanosome ultrastructure were not notably altered by the elution procedure, as determined by electron microscopy. Rat IgG was removed and purified from the trypanosome eluates on an immunoadsorbent column made with the IgG fraction of anti-rat IgG serum coupled to Sepharose beads. Concentrated column eluates, by comparison with a standard, were shown to be rat IgG by immunoelectrophoresis and SDS polyacrylamide gel electrophoresis. As a control, IgG from normal rat serum was purified by the same technique. IgG-negative trypanosomes harvested from immunosuppressed rats bound IgG purified from surface coats of trypanosomes, but not IgG purified from normal rat serum, as demonstrated by subsequent labelling with FITC-conjugated, rabbit anti-rat IgG. The IgG purified from surface coats inhibited the reproduction of T. lewisi in an in vitro assay, but purified, normal IgG did not. These data show that antigen-specific host IgG, adsorbed to the surface of T. lewisi, is ablastic antibody.
宿主免疫球蛋白G（IgG）是路氏锥虫表面被膜的一个组成部分；它是在大鼠感染期间特异性获得的，同时宿主血清中抗锥虫（抑殖）活性的效价会升高。在感染后7至9天，用高盐-低pH缓冲液从锥鞭毛体中洗脱宿主IgG。通过电子显微镜观察发现，洗脱过程并未显著改变表面被膜和锥虫的超微结构。用与琼脂糖珠偶联的抗大鼠IgG血清的IgG组分制成免疫吸附柱，从锥虫洗脱物中去除并纯化大鼠IgG。通过免疫电泳和SDS聚丙烯酰胺凝胶电泳分析，与标准品相比，浓缩的柱洗脱物显示为大鼠IgG。作为对照，用相同技术从正常大鼠血清中纯化IgG。用异硫氰酸荧光素（FITC）偶联的兔抗大鼠IgG进行后续标记，结果表明，从免疫抑制大鼠中收获的IgG阴性锥虫能结合从锥虫表面被膜纯化的IgG，但不能结合从正常大鼠血清中纯化的IgG。在体外试验中，从表面被膜纯化的IgG可抑制路氏锥虫的繁殖，而纯化的正常IgG则无此作用。这些数据表明，吸附在路氏锥虫表面的抗原特异性宿主IgG是一种抑殖抗体。
