title: A recombinant pseudorabies virus expressing TgSAG1 protects against challenge with the virulent Toxoplasma gondii RH strain and pseudorabies in BALB/c mice.
abstract: The major immunodominant surface antigen 1 (TgSAG1) of invasive tachyzoites is a vaccine candidate antigen for Toxoplasma gondii. In this study, we developed a recombinant pseudorabies virus (PRV) expressing TgSAG1 (rPRV/SAG1) based on the PRV vaccine strain Bartha K-61 by homologous recombination, in which partial PK and gG genes were deleted. The growth assay of rPRV/SAG1 showed that the recombinant virus can replicate in vitro as efficiently as PRV Bartha K-61, demonstrating that insertion of the TgSAG1 gene in the PK and gG locus of PRV does not affect the replication of PRV. All mice vaccinated with rPRV/SAG1 developed a high level of specific antibody responses against T. gondii lysate antigen (TLA), a strong increase of the splenocyte proliferative response, and significant levels of IFN-gamma and IL-2 production. And the immunization of mice with rPRV/SAG1 elicited strong cytotoxic T lymphocyte (CTL) responses in vitro. These results demonstrate that rPRV/SAG1 could induce significant humoral and cellular Th1 immune responses. Moreover, rPVR/SAG1 immunization induced partial protection (60%) against a lethal challenge with the highly virulent T. gondii RH strain, and neutralizing antibodies against PRV in a BALB/c mouse model. These results suggest that expression of protective antigens of T. gondii in PRV Bartha K-61 is a novel approach towards the development of a vaccine against both animal toxoplasmosis and pseudorabies.
authors.affiliation: Laboratory of Parasitology, Veterinary Institute, Academy of Military Medical Sciences, Changchun 130062, Jilin Province, China. liuquan1973@hotmail.com
authors.forename: Quan
authors.initials: Q
authors.lastname: Liu
authors.forename: Shengyan
authors.initials: S
authors.lastname: Gao
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.forename: Limin
authors.initials: L
authors.lastname: Shang
authors.forename: Jingtao
authors.initials: J
authors.lastname: Men
authors.forename: Ze
authors.initials: Z
authors.lastname: Wang
authors.forename: Yujia
authors.initials: Y
authors.lastname: Zhai
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Xia
authors.forename: Rongliang
authors.initials: R
authors.lastname: Hu
authors.forename: Xichen
authors.initials: X
authors.lastname: Zhang
authors.forename: Xing-Quan
authors.initials: XQ
authors.lastname: Zhu