The protective effect of a Toxoplasma gondii SAG1 plasmid DNA vaccine in mice is enhanced with IL-18

Res Vet Sci. 2010 Feb 2. [Epub ahead of print]

The protective effect of a Toxoplasma gondii SAG1 plasmid DNA vaccine in mice is enhanced with IL-18

Liu Q, Shang L, Jin H, Wei F, Zhu XQ, Gao H.

Institute of Military Veterinary, Academy of Military Medical Sciences, Changchun 130062, Jilin Province, China.

More effective vaccines against Toxoplasma gondii may contribute to the control of this pathogen that has major veterinary and public health significance. In this study, two recombinant plasmids pcDNA/TgSAG1 and pVAX/mIL-18 containing T. gondii SAG1 (TgSAG1) and murine cytokine interleukin-18 (IL-18) were evaluated for their ability to protect mice against T. gondii challenge. Mice were given two intramuscular immunizations 3weeks apart, and challenged with T. gondii 3weeks later. All animals vaccinated with pcDNA/TgSAG1 alone or with pVAX/mIL-18 developed specific anti-TLA (T. gondii lysate antigen) antibodies and specific lymphocyte proliferative responses. Co-injection of pVAX/mIL-18 significantly increased the production of IFN-gamma and IL-2. Further, challenge experiments showed that co-immunization with pVAX/mIL-18 significantly (P<0.05) increased the survival rate (60%), compared with pcDNA/TgSAG1 alone (40%). Therefore, codelivery of the IL-18-secreting plasmid potentiates the induction and maintenance of the type 1 helper T-cell immune response and may be a potent strategy for enhancing the protective efficacy of vaccines against T. gondii. Copyright © 2010 Elsevier Ltd. All rights reserved.

PMID: 20132954 [PubMed - as supplied by publisher]