title: Molecular identification and characterization of Trichinella spiralis proteasome subunit beta type-7.
abstract: BACKGROUND
  Previous study showed that Trichinella spiralis proteasome subunit beta type-7 (Tspst) gene is an up-regulated gene in intestinal infective larvae (IIL) compared to muscle larvae (ML), which was screened by using suppression subtractive hybridization (SSH) and confirmed by real-time PCR. Tspst may be related to the larval invasion of intestinal epithelial cells (IECs). The aim of this study was to identify Tspst and to investigate its immune protection against intestinal T. spiralis infection.
  
  
  METHODS
  The Tspst gene encoding a 29 kDa protein from T. spiralis infective larvae was cloned, and recombinant Tspst protein (rTspst) was produced in an Escherichia coli expression system. The rTspst was used to immunize BALB/c mice. Anti-rTspst antibodies were used to determine the immunolocolization of Tspst in the parasite. Transcription and expression of Tspst at T. spiralis different developmental stages were observed by RT-PCR and immunofluorescence test (IFT). The in vitro or in vivo immune protection of anti-rTspst serum or rTspst against intestinal T. spiralis infection in BALB/c mice was evaluated.
  
  
  RESULTS
  Anti-rTspst serum recognized the native Tspst protein with 29 kDa in ML crude antigens. Transcription and expression of gene was observed at all T. spiralis different developmental stages (IIL, adult worms, newborn larvae, and ML). An immunolocalization analysis identified Tspst in the cuticle and internal organs of the parasite. An in vitro invasion assay showed that, when anti-rTspst serum, serum of mice infected with T. spiralis or normal mouse serum were added to the medium, the invasion rate of the infective larvae in an IEC monolayer was 25.2%, 11.4%, and 79%, respectively (P < 0.05), indicating that anti-rTspst serum partially prevented the larval invasion of IECs. After a challenge infection with T. spiralis muscle larvae, mice immunized with rTspst conferred a 45.7% reduction in adult worm burden in intestines.
  
  
  CONCLUSIONS
  In the present study, Tspst was first identified and characterized. Tspst is an invasion-related protein of T. spiralis IIL and could be considered as a potential vaccine candidate antigen against intestinal T. spiralis infection that merits further study.
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. ywaenig@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. lilingge1314@163.com.
authors.forename: Ling Ge
authors.initials: LG
authors.lastname: Li
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. liuruodan2006@126.com.
authors.forename: Ruo Dan
authors.initials: RD
authors.lastname: Liu
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. sungege312216@163.com.
authors.forename: Ge Ge
authors.initials: GG
authors.lastname: Sun
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. liuchunying0302@126.com.
authors.forename: Chun Ying
authors.initials: CY
authors.lastname: Liu
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. Shuaibingstudent@163.com.
authors.forename: Shuai Bing
authors.initials: SB
authors.lastname: Zhang
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. jpdaisy@126.com.
authors.forename: Peng
authors.initials: P
authors.lastname: Jiang
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. zhangxi_601@163.com.
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Laboratorial Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, P. R. China. huijunren@126.com.
authors.forename: Hui Jun
authors.initials: HJ
authors.lastname: Ren
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. wangzq@zzu.edu.cn.
authors.forename: Zhong Quan
authors.initials: ZQ
authors.lastname: Wang
authors.affiliation: Department of Parasitology, Medical College of Zhengzhou University, Zhengzhou, 450052, P. R. China. cuij@zzu.edu.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: Cui
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism*; D007814:Larva / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D017160:Trichinella spiralis / Q000235:genetics / Q000378:metabolism*; D014235:Trichinellosis / Q000469:parasitology
chemical_list: D018076:DNA, Complementary; D015801:Helminth Proteins; D046988:Proteasome Endopeptidase Complex