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BioMed Research International
Volume 2017, Article ID 1295038, 6 pages
https://doi.org/10.1155/2017/1295038
Research Article

Resistance to Chronic Toxoplasma gondii Infection Induced by a DNA Vaccine Expressing GRA16

1State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, China
2College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
3Hunan Entry-Exit Inspection and Quarantine Bureau, Changsha, Hunan 410004, China
4Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu 225009, China

Correspondence should be addressed to Nian-Zhang Zhang; moc.361@919gnahznain

Received 26 May 2017; Accepted 9 July 2017; Published 10 August 2017

Academic Editor: Marlene Benchimol

Copyright © 2017 Ling-Ying Hu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Toxoplasma gondii can infect all warm-blooded animals including human beings. T. gondii dense granule protein 16 (TgGRA16) as a crucial virulence factor could modulate the host gene expression. Here, a DNA vaccine expressing TgGRA16 was constructed to explore the protective efficacy against T. gondii infection in Kunming mice. The immune responses induced by pVAX-GRA16 were also evaluated. Mice immunized with pVAX-GRA16 could elicit higher levels of specific IgG antibody and strong cellular response compared to those in controls. The DNA vaccination significantly increased the levels of cytokines (IFN-, IL-2, IL-4, and IL-10) and the percentages of CD4+ and CD8+ T cells in mice. After lethal challenge, mice immunized with pVAX-GRA16 ( days) did not show a significant longer survival time than that in controls ( days) (). However, in chronic toxoplasmosis model (administration of 10 brain cysts of PRU strain orally), numbers of tissue cysts in mice immunized with pVAX-GRA16 were significantly reduced compared to those in controls () and the rate of reduction could reach 43.89%. The results indicated that the TgGRA16 would be a promising vaccine candidate for further development of effective epitope-based vaccines against chronic T. gondii infection in mice.