Anti-tumorimmune effects of WT1 polypeptide vaccine on SCID mice with xenografted human monocytic leukemia / 西安交通大学学报(医学版)

ABSTRACT

Objective: To study the anti-tumor immune effects of WT1 peptide vaccine in SCID mice with xenografted human monocytic leukemia. Methods: Twenty-four hours after intraperitoneal injection of human peripheral blood lymphocytes, the xenograft human monocytic leukemia model in SCID mice was established by subcutaneous inoculation of THP1 cells. The mice were randomly divided into three groups with eight mice in each. Blank control group was vaccinated with incomplete Freund's adjuvant (IAF). Helper T cell epitope group was vaccinated with helper T cell epitopes and IAF. WT1 group was vaccinated with WT1 peptide, helper T cell epitopes and IAF. When the tumor volume grew to 100 mm3, intraperitoneal injection of vaccine components started. The SCID mice were killed 14 days after vaccination. LDH release method was adopted to detect the specific CTL killing activity of spleen cells. Histological characteristics of tumor tissue were observed under microscope after HE staining. Flow cytometry was used to test the levels of peripheral blood CD3+/CD4+T cells, CD3+/CD8+T cells and CD4+CD25+ Treg cells. ELISA method was applied to detect the levels of serum immunoglobulin, IL-2, γ-interferon, TGF-β and IL-10. Results: The xenograft human monocytic leukemia model was successfully established in SCID mice and tumor developed in all the SCID mice. In WT1 group, the activity of mouse spleen cells on THP1 cells was significantly higher than that in helper T cell epitope group and control group (P<0.05). The mean weight and volume of tumor were significantly lower in WT1 group than in helper T cell epitope group and control group (P<0.05). A large amount of tumor cell degeneration and necrosis was observed under the microscope in WT1 group mice and few tumor cells survived. Peripheral blood levels of CD3+/CD4+T cells, CD3+/CD8+T cells, IgG, IFN-γ and IL-2 were all higher in WT1 group than in helper T cell epitope group and control group (P<0.05). However, peripheral blood levels of CD4+/CD25+Treg cells, TGF-β and IL-10 were all lower in WT1 group than in helper T cell epitope group and control group (P<0.05). Conclusion: WT1 polypeptide vaccine can effectively produce anti-tumor immunity and kill leukemia cells in SCID mice with exnografted human monocytic leukemia.