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- Title
Compound DNA vaccine encoding SAG1/ SAG3 with A<sub>2</sub>/B subunit of cholera toxin as a genetic adjuvant protects BALB/c mice against Toxoplasma gondii.
- Authors
Hua Cong; Min Zhang; Qing Xin; Zhiyu Wang; Ying Li; Qunli Zhao; Huaiyu Zhou; Shenyi He
- Abstract
Background: Intracellular parasites, such as T. gondii, present a plurality of antigens because of the complexity of its life cycle. Compound DNA vaccines bring a new approach and hope for the treatment of toxoplasmosis. In this study, a DNA vaccine encoding two major surface antigens SAG1, SAG3 from T. gondii, with A2/B subunit of cholera toxin as a genetic adjuvant was constructed. Methods: BALB/c mice were immunized intramuscularly with PBS, pcDNA3.1, pSAG1, pSAG1/SAG3 and pSAG1/ SAG3-CTXA2/B three times separately. Immunized mice were tested for IgG antibody and IFN-γ and IL-4 production by ELISA. The proliferation of T cells was measured by DNA synthesis assay and the lymphocyte subsets of spleen cells by flow cytometry. All the immunized mice were challenged with 10³ highly virulent RH tachyzoites of Toxoplasma gondii intraperitoneally and the survival times were recorded. Results: An enhanced production of IgG antibodies, antigen-specific lymphocyte proliferation and IFN-γ production from splenic cells were induced in mice immunized with pSAG1/SAG3 compared to mice immunized with pSAG1 (P<0.05). Introduction of CTXA2/B further enhanced the Th1 cell-mediated immunity with higher levels of IFN-γ, lymphocyte proliferation activity and percentage of CD8+ T-cells. When challenged with lethal doses of T. gondii (1x10³), all control mice (PBS and empty plasmid roup) died within 6 days. Mice immunized with pSAG1 died within 8 days. While 20% and 40% survival rate were achieved from mice immunized with pSAG1/SAG3 and pSAG1/SAG3-CTXA2/B. Conclusions: This study indicates the compound DNA vaccine encoding T. gondii antigens SAG1, SAG3 with CTXA2/B gene was a promising DNA vaccine candidate against toxoplasmosis, which could effectively enhance the humoral and cellular immune response and prolong survival time in vaccinated mice.
- Subjects
TOXOPLASMA gondii; CELL surface antigens; VACCINE research; LYMPHOCYTES; PLASMIDS; INTERFERONS
- Publication
Parasites & Vectors, 2013, Vol 6, Issue 1, p1
- ISSN
1756-3305
- Publication type
Article
- DOI
10.1186/1756-3305-6-63