title: Expression, immunolocalization, and serological reactivity of a novel sphingomyelin phosphodiesterase-like protein, an excretory/secretory antigen from Clonorchis sinensis.
abstract: Clonorchiasis, caused by Clonorchis sinensis infection, is a zoonotic parasitic disease of hepatobiliary system in which the proteins released by adult are major pathogenetic factors. In this study, we first characterized a putative sphingomyelin phosphodiesterase (CsSMPase) A-like secretory protein, which was highly expressed in the adult worm. The full-length gene was cloned. The putative protein is of relatively low homology comparing with SMPase from other species, and of rich T cell and B cell epitopes, suggesting that it is an antigen of strong antigenicity. The complete coding sequence of the gene was expressed in the Escherichia coli. The recombinant CsSMPase (rCsSMPase) can be recognized by C. sinensis-infected serum, and the protein immunoserum can recognize a specific band in excretory/secretory products (ESPs) of C. sinensis adult by western blotting. Immunolocalization revealed that CsSMPase was not only localized on tegument, ventral sucker of metacercaria, and the intestine of adult but also on the nearby epithelium of bile duct of the infected Sprague-Dawley rats, implying that CsSMPase was mainly secreted and excreted through adult intestine and directly interacted with bile duct epithelium. Although immunized rats evoked high level antibody response, the antigen level was low in clonorchiasis patients. And the sensitivity and specificity of rCsSMPase were 50.0 % (12/24) and 88.4 % (61/69), in sera IgG-ELISA, respectively. It is likely due to the fact that CsSMPase binding to the plasma membrane of biliary epithelium decreases the antigen immune stimulation.
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Yanwei
authors.initials: Y
authors.lastname: Huang
authors.forename: Youwei
authors.initials: Y
authors.lastname: Zheng
authors.forename: Yuzhe
authors.initials: Y
authors.lastname: Li
authors.forename: Mei
authors.initials: M
authors.lastname: Yang
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.forename: Suxiang
authors.initials: S
authors.lastname: Zeng
authors.forename: Xinbing
authors.initials: X
authors.lastname: Yu
authors.forename: Huaiqiu
authors.initials: H
authors.lastname: Huang
authors.forename: Xuchu
authors.initials: X
authors.lastname: Hu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D000947:Antigens, Helminth / Q000096:biosynthesis*; D001483:Base Sequence; D001652:Bile Ducts / Q000737:chemistry / Q000469:parasitology; D015153:Blotting, Western; D003001:Cloning, Molecular; D003004:Clonorchis sinensis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000737:chemistry; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D004926:Escherichia coli / Q000235:genetics; D020869:Gene Expression Profiling; D015801:Helminth Proteins / Q000096:biosynthesis*; D006801:Humans; D008969:Molecular Sequence Data; D051381:Rats; D017207:Rats, Sprague-Dawley; D017386:Sequence Homology, Amino Acid; D013108:Sphingomyelin Phosphodiesterase / Q000096:biosynthesis*
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; D015801:Helminth Proteins; D013108:Sphingomyelin Phosphodiesterase