Hawn T R, Tom T D, Strand M
Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
J Biol Chem. 1993 Apr 15;268(11):7692-8.
Protective immunity against schistosomiasis induced by vaccination of mice with irradiated cercaria can be passively transferred to uninfected mice with sera or IgG. Antigens that are uniquely or more strongly recognized by such protective sera compared with sera from infected unprotected mice have been identified previously. Two genes, SmIrV1 and SmIrV5, were selected from an adult worm cDNA library by screening with antibodies raised against these candidate vaccine proteins. Active immunization with the SmIrV5 protein induces high levels of protection in mice. We report here the molecular cloning and sequencing of SmIrV1 which contains a deduced amino acid sequence of 582 residues with similarity to three proteins: calnexin, calreticulin, and OvRal1, a surface antigen of the filarial nematode Onchocerca volvulus. SmIrV1 can be divided into three regions: a neutral N-terminal region with a putative signal sequence, followed by a proline- and tryptophan-rich P region in which two sets of sequences are repeated four times and a C-terminal region which is highly acidic with an isoelectric point of 4.7. We expressed the P and C regions of SmIrV1 and showed that this polypeptide reacts with sera of immunized as well as chronically infected mice.
用辐照尾蚴对小鼠进行疫苗接种所诱导的针对血吸虫病的保护性免疫，可通过血清或IgG被动转移至未感染的小鼠。与未受保护的感染小鼠的血清相比，此类保护性血清独特识别或更强烈识别的抗原先前已被鉴定。通过用针对这些候选疫苗蛋白产生的抗体进行筛选，从成虫cDNA文库中选择了两个基因SmIrV1和SmIrV5。用SmIrV5蛋白进行主动免疫可在小鼠中诱导高水平的保护。我们在此报告SmIrV1的分子克隆和测序，其推导的氨基酸序列包含582个残基，与三种蛋白质具有相似性：钙连接蛋白、钙网蛋白以及盘尾丝虫的表面抗原OvRal1。SmIrV1可分为三个区域：具有推定信号序列的中性N端区域，接着是富含脯氨酸和色氨酸的P区域，其中两组序列重复四次，以及C端区域，该区域高度酸性，等电点为4.7。我们表达了SmIrV1的P区域和C区域，并表明该多肽与免疫小鼠以及慢性感染小鼠的血清发生反应。
