Petri W A, Ravdin J I
Department of Medicine, University of Virginia School of Medicine, Charlottesville 22908.
Infect Immun. 1991 Jan;59(1):97-101. doi: 10.1128/iai.59.1.97-101.1991.
No protective antigens from Entamoeba histolytica have been previously defined. We tested the ability of the galactose-specific adherence lectin of E. histolytica to elicit a protective immune response in conjunction with Freund's incomplete and complete adjuvants. The gerbil (Meriones unguiculatus) model of an experimental amebic liver abscess was used. Gerbils were immunized intraperitoneally or subcutaneously with 10 micrograms of the affinity-purified lectin in complete Freund's adjuvant and then at 2 and 4 weeks with 10 micrograms of the lectin in incomplete Freund's adjuvant. All of the immunized animals developed antilectin antibody titers of greater than 1/1,024 as measured by a radioimmunoassay. The gerbil antilectin antibodies were shown by Western immunoblotting to be directed to the heavy subunit but not the light subunit of the lectin. Immune gerbil sera inhibited amebic adherence by 100% at a 1/10 dilution. Immune and control gerbils were challenged at 6 weeks by the intrahepatic injection of 5 x 10(5) E. histolytica trophozoites. Four independent trials demonstrated complete protection from amebic liver abscess formation in 67% of lectin-immunized gerbils. Unexpectedly, liver abscess weights were significantly higher in the gerbils that failed to become immune than in the control animals. Our results demonstrate that the galactose lectin is a protective antigen and provide an immune-animal model to study the mechanisms of protection and potential disease exacerbation conferred by the antilectin immune response.
此前尚未明确溶组织内阿米巴的保护性抗原。我们测试了溶组织内阿米巴的半乳糖特异性黏附凝集素与弗氏不完全佐剂和完全佐剂联合使用时引发保护性免疫反应的能力。使用了实验性阿米巴肝脓肿的沙鼠（长爪沙鼠）模型。沙鼠腹腔内或皮下注射10微克亲和纯化的凝集素与完全弗氏佐剂，然后在第2周和第4周注射10微克凝集素与不完全弗氏佐剂。通过放射免疫测定法测量，所有免疫动物产生的抗凝集素抗体滴度均大于1/1024。通过蛋白质印迹法显示，沙鼠抗凝集素抗体针对的是凝集素的重亚基而非轻亚基。免疫沙鼠血清在1/10稀释度时可100%抑制阿米巴黏附。在第6周时，对免疫沙鼠和对照沙鼠进行肝内注射5×10⁵个溶组织内阿米巴滋养体的攻击。四项独立试验表明，67%的凝集素免疫沙鼠完全免受阿米巴肝脓肿形成。出乎意料的是，未产生免疫的沙鼠肝脏脓肿重量显著高于对照动物。我们的结果表明，半乳糖凝集素是一种保护性抗原，并提供了一个免疫动物模型来研究抗凝集素免疫反应所赋予的保护机制和潜在的疾病加重情况。
