A recombinant pseudorabies virus expressing TgSAG1 protects against challenge with the virulent Toxoplasma gondii RH strain and pseudorabies in BALB/c mice

• Published in: Microbes and infection 2008-10, Vol.10 (12), p.1355-1362
• Main Authors: Liu, Quan, Gao, Shengyan, Jiang, Li, Shang, Limin, Men, Jingtao, Wang, Ze, Zhai, Yujia, Xia, Zhiping, Hu, Rongliang, Zhang, Xichen, Zhu, Xing-Quan
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Protozoan - blood; Antibodies, Viral - blood; Antigens, Protozoan - genetics; Antigens, Protozoan - immunology; Antigens, Protozoan - metabolism; Applied microbiology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Herpesvirus 1, Suid - genetics; Herpesvirus 1, Suid - immunology; Herpesvirus 1, Suid - metabolism; Herpesvirus 1, Suid - pathogenicity; Immunity; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Microbiology; Miscellaneous; Protozoan Proteins - genetics; Protozoan Proteins - immunology; Protozoan Proteins - metabolism; Protozoan Vaccines - administration & dosage; Protozoan Vaccines - genetics; Protozoan Vaccines - immunology; Pseudorabies - immunology; Pseudorabies - prevention & control; Pseudorabies - virology; Pseudorabies Vaccines - administration & dosage; Pseudorabies Vaccines - genetics; Pseudorabies Vaccines - immunology; Pseudorabies virus; Recombination, Genetic; TgSAG1; Toxoplasma - genetics; Toxoplasma - immunology; Toxoplasma - metabolism; Toxoplasma - pathogenicity; Toxoplasma gondii; Toxoplasmosis, Animal - immunology; Toxoplasmosis, Animal - parasitology; Toxoplasmosis, Animal - prevention & control; Vaccination; Vaccine; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, DNA - administration & dosage; Vaccines, DNA - genetics; Vaccines, DNA - immunology; Virology
• ISSN: 1286-4579; 1769-714X
• DOI: 10.1016/j.micinf.2008.08.002

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-γ 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.