Huggins M C, Gibbs J, Moloney N A
Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK.
Mol Biochem Parasitol. 1995 Apr;71(1):81-7. doi: 10.1016/0166-6851(95)00038-3.
A recombinant lambda gt11 clone, IVGS3, encoding part of a 55-kDa antigen was isolated from an adult Schistosoma japonicum cDNA library. The protein expressed by this clone was recognised strongly by serum from rats that had been vaccinated with irradiated cercariae (VrS) rendering them highly immune to a challenge infection. Antibodies in VrS which were specific for IVGS3 did not recognise adult worm antigens of S. mansoni, suggesting that the recombinant antigen contains species-specific epitopes, although IVGS3 was weakly recognised by rat serum raised against irradiated S. mansoni cercariae, indicating the presence of a related antigen in this species. A further clone, AM1(p), was obtained which, together with IVGS3 encompasses the entire coding region of the gene which has been called Sj55. Sequence analysis revealed similarities with murine calreticulin, a protein resident in the endoplasmic reticulum. As with murine calreticulin, Sj55 was shown to be a calcium-binding protein. Antigens with homologies to calreticulin have also been described in two other helminths, S. mansoni and Onchocerca volvulus.
从日本血吸虫成虫cDNA文库中分离出一个编码55 kDa抗原部分片段的重组λgt11克隆IVGS3。该克隆表达的蛋白能被经辐照尾蚴免疫的大鼠血清（VrS）强烈识别，使这些大鼠对攻击感染具有高度免疫力。VrS中对IVGS3特异的抗体不能识别曼氏血吸虫成虫抗原，这表明重组抗原含有种特异性表位，尽管IVGS3能被经辐照的曼氏血吸虫尾蚴免疫的大鼠血清弱识别，提示该物种中存在相关抗原。又获得了另一个克隆AM1(p)，它与IVGS3一起涵盖了已命名为Sj55的基因的整个编码区。序列分析显示其与内质网驻留蛋白小鼠钙网蛋白相似。与小鼠钙网蛋白一样，Sj55被证明是一种钙结合蛋白。在另外两种蠕虫曼氏血吸虫和盘尾丝虫中也描述了与钙网蛋白具有同源性的抗原。
