Protective effect of DNA-mediated immunization with liposome-encapsulated GRA4 against infection of Toxoplasma gondii

作     者：Rui CHEN Shao-hong LU Qun-bo TONG Di LOU Dong-yan SHI Bing-bing JIA Guo-ping HUANG Jin-fu WANG 

作者机构：College of Life Sciences Zhejiang University Hangzhou 310058 China Institute of Parasitology Zhejiang Academy of Medical Science Hangzhou 310013 China 

出 版 物：《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 (浙江大学学报（英文版）B辑（生物医学与生物技术）)

年 卷 期：2009年第10卷第7期

页      面：512-521页

核心收录：

学科分类：090603[农学-临床兽医学] 1007[医学-药学(可授医学、理学学位)] 09[农学] 0906[农学-兽医学] 10[医学] 

基　　金：supported by the Science Foundation of the Health Bureau of Zhejiang Province, China (Nos. 2003QN003 and 2005A001) the Science Foundation of the Science and Technology Department of Zhejiang Province, China (No. 2006C13022) 

主　　题：DNA vaccine Granule protein 4 (GRA4) Liposome Toxoplasma gondii 

摘      要：The dense granule protein 4 （GRA4） is a granular protein from Toxoplasma gondii, and is a candidate for vaccination against this parasite. In this study, the plasmid pcDNA3, 1-GRA4 （pGRA4）, encoding for the GRA4 antigen, was incorporated by the dehydration-rehydration method into liposomes composed of 16 mmol/L egg phosphatidylcholine （PC）, 8 mmol/L dioleoyl phosphatidylethanolamine （DOPE）, and 4 mmol/L 1,2-diodeoyl-3-（trimethylammonium） propane （DOTAP）. C57BL/6 mice and BALB/c mice were immunized intramuscularly three times with liposome-encapsulated pGRA4 to determine whether DNA immunization could elicit a protective immune response to T. gondii. Enzyme-linked immunosorbent assay （ELISA） of sera from immunized mice showed that liposome-encapsulated pGRA4 generated high levels of IgG antibodies to GRA4. Production of primary interferon （IFN）-7 and interleukin （IL）-2 in GRA4-stimulated splenocytes from vaccinated mice suggested a modulated Th 1-type response. 72.7% of C57BL/6 mice immunized with liposome-encapsulated pGRA4 survived the challenge with 80 tissue cysts of ME49 strain, whereas C57BL/6 mice immunized with pGRA4 had only a survival rate of 54.5%. When immunized BALB/c mice were intraperitoneally challenged with 103 tachyzoites of the highly virulent RH strain, the survival time of mice immunized with liposome-encapsulated pGRA4 was markedly longer than that of other groups. Our observations show that liposome-encapsulated pGRA4 enhanced the protective effect against infection of T. gondii.