Evaluation on immunizing effect and route of plural DNA vaccine to Toxoplasma gondii

  Objective   To assess the effect of plural DNA vaccination on Toxoplama gondii via different immunized routes.

  Methods   Recombinant plasmid pSAG1-2-CTA₂/B encoding SAG1 and SAG2 of T.gondii antigen and CTA₂/B subunit of cholera toxin was constructed by gene engineering.Largescale preparation of plasmid DNA by alkaline lysis.BALB/ c mice were immunized intramuscular or intranasal with plasmid pSAG1-2-CTA₂/B.Booster immunizations were employed 2 more times at 2-week interval.Humoral and cellular responses were assayed using ELISA for the determination of Ab and IFN-γ, as well as IL-4, the proliferation activity of T lymph cells and the activity of NK killer by means of methyl thiazolyl tetrazolium(MTT)assay, flow cytometry(FCM)was also used to sort the lymphocyte subsets of spleen cells.

  Results   Humoral and cellular immuno-response are enhanced in mice immunized via both of the two routes and most prolonged survival time was got in this challenging vaccinated mice group.While only high level of Ig G or only high level of cellular was detected in mice immunized intramuscular or intranasal.

  Conclusion   The immunity of DNA vaccine of T.gondii could be enhanced markedly by immunized mice via several route.