Anti-Tumor Immunity Elicited by Peptide Complex-Alpha-Fetoprotein and Glycoprotein 96

Abstract

Purposes: To construct a recombinant vaccine alpha-fetoprotein (AFP)-glycoprotein (gp96) complex, and study its ability to induce specific CTL response and its protective effect against AFP-producing tumor. Material/Methods: A recombinant vaccine was constructed by conjugating mouse alpha-fetoprotein to glycoprotein 96. By way of intracutaneous injection, mice were primed and boosted with recombinant vaccine mAFP/gp96, whereas single mAFP or gp96 injection as controls. The ELISPOT and ELISA were used to measure the frequency of cells producing the cytokine IFN-gama in splenocytes and the level of anti-AFP antibody of serum from immunized mice respectively. In vivo tumor challenge was carried out to assess the immune effect of the recombinant vaccine. Results: By recombinant mAFP/gp96 vaccine immunization, the results of ELISPOT and ELISA showed that the number of splenic cells producing IFN-gama and the level of anti-AFP antibody of serum were significantly higher in mAFP/gp96 group than those in mAFP and gp96 groups (122.50±9.30 IFN-gama spots/106 cells vs 46.40±10.32 IFN-gama spots/106 cells, 12.14±7.33 IFN-gama spots/106 cells, P<0.01; 164.52±11.22 µg/mL vs 56.32±8.23 µg/mL, 7.56±3.47 µg/mL, P< 0.01). The tumor volume in mAFP/gp96 group was significantly smaller than that in mAFP and gp96 groups (32.46±6.35 mm3 vs 384.16±11.43 mm3, 832.54±12.72 mm3, P< 0.01). Conclusions: The study further confirmed the function of glycoprotein 96s immune adjuvant. Sequential immunization with recombinant mAFP/gp96 vaccine could generate effective antitumor immunity on AFP-producing tumor. The recombined mAFP/gp96 vaccine may be suitable for serving as an immunotherapy for hepatocellular carcinoma.