title: Cloning, expression and characterization of protein disulfide isomerase of Schistosoma japonicum.
abstract: The excretory/secretory (ES) proteins of schistosomes play important roles in modulating host immune systems and are regarded as potential vaccine candidates and drug targets. Protein disulfide isomerase (PDI) is an essential enzyme that is involved in disulfide bond formation and rearrangement. In the present study, SjPDI, a 52.8 kDa protein previously identified in a proteomics analysis as one of the ES proteins of Schistosoma japonicum, was cloned and characterized. Western blot analysis showed that recombinant SjPDI (rSjPDI) was recognized by serum from rabbits vaccinated with schistosome worm antigen. Worm protein extracts and ES protein extracts from S. japonicum could react with anti-rSjPDI mouse serum. Real-time PCR analysis indicated that SjPDI was expressed at all developmental stages tested, and a high expression level was detected in 42-day-old male worms. Immunofluorescence analysis revealed that SjPDI was mainly distributed on the tegument and parenchyma of S. japonicum worms. An enzyme-linked immunosorbent assay (ELISA) demonstrated that rSjPDI could induce a high level of rSjPDI-specific IgG antibodies. The biological activity of purified rSjPDI was confirmed by isomerization and antioxidative activity assays. The 35.32%, 26.19% reduction in the worm burden and 33.17%, 31.7% lower liver egg count were obtained in mice vaccinated with rSjPDI compared with the blank control group in two independent trials. Our preliminary results suggest that rSjPDI plays an important role in the development of the schistosome and is a potential vaccine candidate for schistosomiasis.
authors.affiliation: Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology, Ministry of Agriculture of China, Shanghai, China.
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Cao
authors.forename: Yang
authors.initials: Y
authors.lastname: Hong
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Han
authors.forename: Miaoli
authors.initials: M
authors.lastname: Wu
authors.forename: Xinzhuo
authors.initials: X
authors.lastname: Wang
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Guo
authors.forename: Changjian
authors.initials: C
authors.lastname: Li
authors.forename: Ke
authors.initials: K
authors.lastname: Lu
authors.forename: Hao
authors.initials: H
authors.lastname: Li
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Fu
authors.forename: Jiaojiao
authors.initials: J
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D015153:Blotting, Western; D003001:Cloning, Molecular; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D007114:Immunization / Q000379:methods; D007074:Immunoglobulin G / Q000097:blood; D008099:Liver / Q000469:parasitology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010802:Phylogeny; D019704:Protein Disulfide-Isomerases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D011897:Random Allocation; D012549:Schistosoma japonicum / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D016415:Sequence Alignment; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000909:Antibodies, Helminth; D007074:Immunoglobulin G; D012333:RNA, Messenger; D014614:Vaccines, Synthetic; D019704:Protein Disulfide-Isomerases