AUTHOR=Zhou Jian , Wang Lin 

TITLE=SAG4 DNA and Peptide Vaccination Provides Partial Protection against T. gondii Infection in BALB/c Mice

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01733

DOI=10.3389/fmicb.2017.01733

ISSN=1664-302X

ABSTRACT=<p><italic>Toxoplasma gondii</italic> can lead to congenital infections in human. Surface antigen protein 4 (SAG4) of <italic>T. gondii</italic> is a potential stimulator for humoral and cellular immune responses. In the present study, a DNA vaccine encoding SAG4 from <italic>T. gondii</italic> was constructed and used to immunize BALB/c mice with peptide to evaluate the protective efficacy of the vaccine. The productions of IgG antibodies and cytokines (gamma interferon) from the vaccine (pSAG4/peptide) group were significantly higher than pSAG4 or peptide groups. After a lethal challenge by 1 × 10<sup>4</sup> tachyzoites from the I strain (RH), the survival time of mice immunized by pSAG4/peptide was longer than that of pSAG4 or peptide immunized mice or control mice. Moreover, after challenging by 20 cysts of the II strain (PRU) of <italic>T. gondii</italic>, the number of brain cysts from pSAG4/peptide vaccinated mice was only 31% of the number in PBS injected mice. The findings suggested the SAG4 DNA vaccine with peptide led significant immune responses and improved the protection against <italic>T. gondii</italic> challenges.</p>