Antitumor Immunity Induced by Recombinant Vaccine Alpha-Fetoprotein-Heat Shock Protein 70 Complex

To construct a recombinant vaccine alpha-fetoprotein (AFP)-heat shock protein (HSP70) complex, and study its ability to induce specific cytotoxic T lymphocyte (CTL) response and its protective effect against AFP-producing tumor. A recombinant vaccine was constructed by conjugating mouse heat shock protein 70. By way of intracutaneous injection, mice were primed and boosted with recombinant vaccine mAFP/HSP70, whereas single mAFP or HSP70 injection as controls. The ELISPOT and ELISA were used to measure the frequency of cells producing the cytokine IFN-gamma in splenocytes and the level of anti-AFP antibody of serum from immunized mice respectively. In vivo tumor challenge were carried out to assess the immune effect of the recombinant vaccine. By recombinant mAFP/HSP70 vaccine immunization, the results of ELISPOT and ELISA showed that the number of splenic cells producing IFN-gamma and the level of anti-AFP antibody of serum were significantly higher in mAFP/HSP70 group than those in mAFP and HSP70 groups (108.50 plusmn 11.70 IFN-gamma spots/10⁶ cells vs 41.60 plusmn 10.40 IFN-gamma spots/10⁶ cells, 7.32 plusmn 3.14 IFN-gamma spots/10⁶ cells, P<0.01; 156.32 plusmn10.42 mug/mL vs 66.52 plusmn 7.35 mug/mL, 5.73 plusmn 2.89 mug/mL, P<0.01). The tumor volume in mAFP/HSP70 group was significantly smaller than that in mAFP and HSP70 groups (42.44 plusmn 7.14 mm³ vs 392.23 plusmn 12.46 mm³, 838.63 plusmn 13.84 mm³, P<0.01). The study further confirmed the function of heat shock protein 70´s immune adjuvant. Sequential immunization with recombinant mAFP/HSP70 vaccine could generate effective antitumor immunity on AFP-producing tumor. The recombined mAFP/HSP70 vaccine may be suitable for serving as an immunotherapy for HCC.