1.The Study on the Anti-HBV Effect of Whole Live Recombinant Yeast as Therapeutic Vaccine 2.The Study on the Anti-HBV Immunity Induced by Human Cord Blood-Derived Dendritic Cells Pulsed with HBsAg

Abstract: Objective: Based on the expressing and immunologic characteristic of yeast, a new therapeutic vaccine, whole recombinant yeast expressing HBsAg or fusion protein of HBsAg and HSP70 (1-370), was used to explore a new way to activate cell-mediated anti-HBV immunity. Methods: The recombinant plasmids, pYES2-S, was constructed by inserting the HBsAg gene into the vector pYES2 .The recombinant plasmids, pPIC9K/S and PIC9K/hsp (1-370)-S, were constructed in a similar way. Then those recombinants were electro-transfected into Saccharomyces cerevisiae, INVSc-1, or Pichia pastoris, GS115, respectively. BALB/C mice were immunized with whole recombinant live yeast subcutaneously for 4 times. The humoral immunity to HBsAg was detected through ELISA assay of anti-HBsAg in mice’s serum; The ELISA assay was also used to detect the secretion of cytokine after the splenocytes were co-incubated with HBsAg for 72 hours. HBsAg-specific T cells proliferation was assayed though [3H] thymidine incorporation. Results: Recombinant whole live yeast successfully activated the humoral immunity, which showed that the reconstruction process had kept the antigenicity of HBsAg intact. On one hand, [3H] thymidine incorporation showed that there were HBsAg-specific T cells existing in mice immunized with whole recombinant Saccharomyces cerevisiae, on the other hand, the immunization with whole recombinant Pichia pastoris could facilitate the secretion of mIL-2 of those mice’ splenocytes. Conclusion: The whole recombinant live yeast may be used as therapeutic vaccine, but further study is needed for optimal way of immunization…
Key words: Saccharomyces cerevisiae; Pichia pastoris yeast; Therapeutic vaccine.