Schistosoma Japonicum UDP-Glucose 4-Epimerase Protein Is Located on the Tegument and Induces Moderate Protection against Challenge Infection

Pingping Liu,Yanli Shi,Jiaojiao Lin,Yamei Jin,Yufan Cao,Jinming Liu,Yaojun Shi,Yunxia Yang,Hao Li,Paulo Lee Ho

doi:10.1371/journal.pone.0042050

Abstract

Schistosomiasis is an important global public health problem, as millions of people are at risk of acquiring this infection. An ideal method for sustainable control of schistosomiasis is using a vaccine alone or in combination with drugs. In the present study, we cloned the SjGALE gene and generated the expression product in E. coli. The expression level of SjGALE during different developmental stages of S. japonicum was evaluated by real-time RT-PCR and western blotting. Immunolocalization indicated that the protein was mainly located on the tegument of the parasite. Infection of rSjGALE-immunized mice demonstrated a 34% and 49% reduction of the mean worm burden and liver egg burden, respectively, in two independent experiments, indicating immune protection. The liver egg count from each female adult worm was significantly reduced by 63% in the two trials. The cytokine profile and IgG isotype analysis demonstrated the induction of a Th1 immune profile in response to immunization with this protein, further suggesting protection against infection. In conclusion, these findings indicated that SjGALE is a potential vaccine against S. japonicum.

Highlights

Schistosomiasis is an important helminth infection and mainly occurs in developing countries
Novel potential vaccine antigens were evaluated, but the level of protection obtained by vaccination with these antigens rarely exceeded the 40% benchmark set by the The World Health Organization (WHO) [6]
We cloned and expressed full-length SjGALE cDNA and analyzed its expression level at different stages of schistosomal developmental and the localization of the protein. We evaluated this protein as a vaccine candidate in vivo by examining the SjGALE-induced humoral and cellular immune protective mechanisms in a mouse model of schistosomal infection

Summary

Introduction

Schistosomiasis is an important helminth infection and mainly occurs in developing countries. There are still millions of people at risk of contracting this infection [1]. Current schistosomiasis control strategies are mainly based on safe and effective drugs, such as praziquantel and oxamniquine, but these do not prevent reinfection and the number of infected people has remained constant [2,3]. The best long-term strategy to control schistosomiasis is through immunization with an antischistosomiasis vaccine combined with drug treatment [4]. Novel potential vaccine antigens were evaluated, but the level of protection obtained by vaccination with these antigens rarely exceeded the 40% benchmark set by the The World Health Organization (WHO) [6]. It is necessary to search for alternative highly protective vaccine candidates

Methods

Results

Conclusion