Seeber F, Brattig N, Soboslay P T, Pogonka T, Lörz A, Strote G, Beck E, Titanji V P, Lucius R
Institut für Tropenhygiene, University of Heidelberg, Germany.
J Immunol. 1993 Apr 1;150(7):2931-44.
To identify potentially protective Ag of the filarial nematode Onchocerca volvulus on the molecular level we screened a cDNA library of O. volvulus with a human serum raised against radiation-attenuated infective larvae of O. volvulus. A cDNA clone of 218 bp (OvL3-1) was selected for further studies. It was expressed in Escherichia coli and affinity purified recombinant polypeptide was tested for its ability to stimulate in vitro PBMC from African onchocerciasis patients and PBMC from chimpanzees experimentally infected with O. volvulus. An enhanced cell proliferation by PBMC was observed in many patients after stimulation with the recombinant OvL3-1 polypeptide. In addition, some patients' PBMC responded to OvL3-1 stimulation with enhanced IL-2 production. Infected chimpanzees also showed an increase in T cell proliferation. Onchocerciasis patients had variable levels of specific antibodies directed to the recombinant polypeptide when sera were tested by ELISA. A mAb directed against the recombinant protein located the native target Ag in the muscles of the adult worm. The molecular mass of native OvL3-1 was found to be 50 kDa on immunoblots. Polymerase chain reaction analysis of RNA from different life stages of the parasite showed that OvL3-1 is transcribed in all parasite stages within the mammalian host. A homologous gene is also present in other filarial parasites. The protein corresponding to OvL3-1, therefore, represents an immunogen present during the whole life-span of the parasite, and because of its B and T cell stimulatory properties, it may be a candidate for a protective Ag in human filariasis.
为了在分子水平上鉴定盘尾丝虫潜在的保护性抗原，我们用针对经辐射减毒的盘尾丝虫感染性幼虫免疫的人血清筛选了盘尾丝虫的cDNA文库。选择了一个218 bp的cDNA克隆（OvL3-1）进行进一步研究。它在大肠杆菌中表达，对亲和纯化的重组多肽进行了检测，以评估其刺激非洲盘尾丝虫病患者的体外外周血单核细胞（PBMC）以及实验感染盘尾丝虫的黑猩猩的PBMC的能力。在用重组OvL3-1多肽刺激后，许多患者的PBMC出现细胞增殖增强。此外，一些患者的PBMC对OvL3-1刺激的反应是白细胞介素-2产生增加。感染的黑猩猩也表现出T细胞增殖增加。当通过酶联免疫吸附测定（ELISA）检测血清时，盘尾丝虫病患者针对重组多肽的特异性抗体水平各不相同。一种针对重组蛋白的单克隆抗体在成虫的肌肉中定位到了天然靶抗原。在免疫印迹上发现天然OvL3-1的分子量为50 kDa。对来自寄生虫不同生活阶段的RNA进行聚合酶链反应分析表明，OvL3-1在哺乳动物宿主体内的所有寄生虫阶段均有转录。其他丝虫寄生虫中也存在同源基因。因此，与OvL3-1对应的蛋白代表了寄生虫整个生命周期中存在的一种免疫原，由于其具有刺激B细胞和T细胞的特性，它可能是人类丝虫病保护性抗原的一个候选物。
