[Antitumor effect of EGFRvIII/HBcAg recomibinant vaccine on murine transplanted tumor].

AIM: To explore the immune effect of the recomibinant fusion protein EGFRvIII/HBcAg on murine transplanted EGFRvIII positive tumor in vivo.

METHODS: BALB/c mice(30) were ramdomedly divided into three groups and immunized by fusion protein, HBcAg and normal sodium(NS). When the antibody titre of the mice immunized by fusion protein reached 1:20 000, the immunization was terminated and the positive renca cells of EGFRvIII were inoculated subcutaneouly into BALB/c mice. The antitumor effect was observed in vivo. Using HE and immunohistochemistry image analysis, the tumor necrosis and EGFRvIII expression were compared among three groups.

RESULTS: Tumor growth was inhibited by fusion protein. The tumorigenic rate of fusion protein group, HBcAg group and NS group was 50%, 100% and 100% respectively. Tumor grew fastest in NS group but tumor grew with the slowest speed in fusion protein group. The average tumor weight of fusion protein group was significantly lighter than that of the other two groups (t=4.731, P=0.044; t=6.890, P=0.040), and there was no statistical difference between normal sodium group and HBcAg group (t=0.024, P=0.382). Tumor necrosis was much severe in fusion group. Immunohistochemistry analysis showed that the expression level of EGFRvIII in fusion protein group was lower than that in NS group and HBcAg group(t=3.157, P=0.006; t=2.539, P=0.021), and no statistical difference was observed between the two groups(t=0.460, P=0.651).

CONCLUSION: The fusion protein EGFRvIII/HBcAg can induce the protective antitumor immunity against EGFRvIII-positive tumor.