Molecular characterization and protective efficacy of the microneme 2 protein from Eimeria tenella.

Ming Yan,Hui Dong,Huanzhi Zhao,Bing Huang,Lu Wang,Qiping Zhao,Xiaoxia Cui,Guiling Liu,Zhihang Li,Hongyu Han,Shunhai Zhu

doi:10.1051/parasite/2018061

Abstract

Microneme proteins play an important role in the adherence of apicomplexan parasites to host cells during the invasion process. In this study, the microneme 2 protein from the protozoan parasite Eimeria tenella (EtMIC2) was cloned, characterized, and its protective efficacy as a DNA vaccine investigated. The EtMIC2 gene, which codes for a 35.07 kDa protein in E. tenella sporulated oocysts, was cloned and recombinant EtMIC2 protein (rEtMIC2) was produced in an Escherichia coli expression system. Immunostaining with an anti-rEtMIC2 antibody showed that the EtMIC2 protein mainly localized in the anterior region and membrane of sporozoites, in the cytoplasm of first- and second-generation merozoites, and was strongly expressed during first-stage schizogony. In addition, incubation with specific antibodies against EtMIC2 was found to efficiently reduce the ability of E. tenella sporozoites to invade host cells. Furthermore, animal-challenge experiments demonstrated that immunization with pcDNA3.1(+)-EtMIC2 significantly increased average body weight gain, while decreasing the mean lesion score and oocyst output in chickens. Taken together, these results suggest that EtMIC2 plays an important role in parasite cell invasion and may be a viable candidate for the development of new vaccines against E. tenella infection in chickens.

Highlights

Avian coccidiosis, a protozoan parasitic disease caused by the intracellular apicomplexan parasite, Eimeria spp., leads to heavy economic losses in the poultry industry worldwide [5]
The E. tenella microneme-2 gene (EtMIC2) gene was isolated from Complementary DNA (cDNA) of sporulated oocysts from the E. tenella Shanghai strain
The obtained sequence showed 99%–100% identity with the available EtMIC2 genes deposited in GenBank, indicating that the EtMIC2 gene is highly conserved among the different strains of E. tenella [37]

Summary

Introduction

A protozoan parasitic disease caused by the intracellular apicomplexan parasite, Eimeria spp., leads to heavy economic losses in the poultry industry worldwide [5]. It causes an estimated loss of more than $3 billion USD per. There has been an increased effort to develop new control strategies for Eimeria infection that target multiple stages of the parasitic invasion process. One of these approaches is to block the invasion of Eimeria into intestinal epithelial cells to prevent coccidiosis

Methods

Results

Conclusion