Protective immunity against Trichinella spiralis infection induced by TsNd vaccine in mice.

Ling Ge Li,Ruo Dan Liu,Li Na Liu,Pei Liu,Xin Zhuo Zhang,Peng Jiang,Zhong Quan Wang,Min Wang,Shuai Bing Zhang,Jing Cui,Shao Rong Long

doi:10.1186/s13071-015-0791-8

Ling Ge Li, Ruo Dan Liu + Show 9 more

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https://doi.org/10.1186/s13071-015-0791-8

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Abstract

BackgroundWe have previously reported that Trichinella spiralis Nudix hydrolase (TsNd) bound to intestinal epithelial cells (IECs), and vaccination of mice with recombinant TsNd protein (rTsNd) produced a partial protective immunity. The aim of this study was to investigate the immune protection induced by TsNd DNA vaccine.MethodsThe full-length cDNA sequence of TsNd gene was cloned into pcDNA3.1 and used to immunize BALB/c mice by intramuscular injection. Transcription and expression of TsNd were detected by RT-PCR and IFT. The levels of specific IgA, IgG, IgG1 and IgG2a, and cytokines were assayed by ELISA at weeks 0, 6 and 8 post-immunization. The immune protection of TsNd DNA vaccine against challenge infection was investigated.ResultsImmunization of mice with TsNd DNA elicited a systemic Th1/Th2 immune response and a local mucosal IgA response. The in vitro transcription and expression of TsNd gene was observed at all developmental stages of T. spiralis (ML, IIL, AW and NBL). Anti-rTsNd IgG levels were increased after immunization and levels of IgG1 were obviously higher than that of IgG2a. Intestinal specific IgA levels of immunized mice were significantly higher than those of vector and PBS control mice. Cytokine profiling also showed a significant increase in Th1 (IFN-γ, IL-2) and Th2 (IL-4, 10) responses in splenocytes of immunized mice on stimulation with rTsNd. Vaccination of mice with pcDNA3.1-TsNd displayed a 40.44% reduction in adult worms and a 53.9% reduction in larval burden.ConclusionsTsNd DNA induced a mixed Th1/Th2 immune response and partial protection against T. spiralis infection in mice.

Highlights

We have previously reported that Trichinella spiralis Nudix hydrolase (TsNd) bound to intestinal epithelial cells (IECs), and vaccination of mice with recombinant TsNd protein produced a partial protective immunity
Construction of recombinant pcDNA3.1-TsNd The full-length cDNA encoding TsNd was cloned into pcDNA3.1, the recombinant plasmid pcDNA3.1-TsNd was digested with BamHI/XhoI and the results revealed that the recombinant plasmid contained an insert of about 1248 bp (Figure 1)
Sequence analysis indicated that the amplified fragment of TsNd consisted of 1248 bp, and the predicted open reading frame (ORF) encoded a protein of 415 amino acid residues with a molecular mass of 46 kDa and 99.7% identity to the published sequence of TsNd in GenBank (EU263318.1)

Summary

Introduction

We have previously reported that Trichinella spiralis Nudix hydrolase (TsNd) bound to intestinal epithelial cells (IECs), and vaccination of mice with recombinant TsNd protein (rTsNd) produced a partial protective immunity. The aim of this study was to investigate the immune protection induced by TsNd DNA vaccine. Trichinella spiralis is a parasitic nematode that infects humans and other mammals [1]. In the past several decades, many outbreaks of human trichinellosis have been reported in different areas of the world [3]. From 2004 to 2009, 15 outbreaks of human trichinellosis, with 1387 cases and 4 deaths, were reported in China [4]. T. spiralis Nudix hydrolase (TsNd) protein binding to

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