CD 3/KIF20A bispecific antibody mediated anti-tumor effects of T lymphocytes on KIF20A positive PANC1 cells / 中华胰腺病杂志

ABSTRACT

Objective:To investigate the induction of specific T lymphocyte by bispecific monoclonal antibody in pancreatic cancer and its killing effects on KIF20A positive pancreatic cancer PANC1 cell line.Methods:CD 3/KIF20A bispecific monoclonal antibody was prepared and concentrated by chemical cross-linking method and purified by Sephrose-25 gel chromatography. Peripheral blood samples of healthy volunteers were collected, and monocytes were isolated using lymphocyte separation solution, and then cultured as dendritic cells (DC) and T cells respectively, and then co-cultured as DC-T cells. Meanwhile vitamin C was used to treat DC-T cells (vcDC-T cells). The levels of IFN-γ, IL-2, IL-4 and IL-12 in the supernatants and T cell subsets were detected by flow cytometry. About 1×10 5 T cells, DC-T cells, and vcDC-T cells with 10, 50, 100 and 300 ng CD 3/KIF20A antibody loaded were cocultured with PANC1 cells (20∶1) for 2, 6 and 10 hours to determine the highest killing rate dosage of CD 3/KIF20A antibody loaded cells. DC-T cells and DC-T cells, vcDC-T cells loaded with the highest killing rate dosage of CD 3/KIF20A antibody were cocultured with PANC1 cells (20∶1) for 2, 6, 8, 10 and 12 hours. The aggregation effect of effector cells on target cells was observed under inverted microscope, the killing rate of tumor cells was detected by LDH method. Results:The molecular weight of CD 3/KIF20A antibody was 130 000 measured and validated by SDS gel electrophoresis. The ratio of CD 8+ CD 28+ and CD40L subsets of vcDC-T cells was increased [(47.6±15.8)% vs (38.2±7.6)%, (52.1±4.9)% vs (44.7±3.2)% ] compared with that of DC-T cells, the ratio of negative regulatory cells (Treg) was decreased [(4.3±0.8)% vs (8.3±1.1)%]; the release of IL-2, IFN-γ and IL-12 was increased [(201.2±17.3) ng/L, (163.4±13.1)ng/L, (303.3±22.6)ng/L vs 221.8±17.6)ng/L, (190.4±11.7)ng/L vs (80.3±8.6)ng/L]. All the differences were statistically significant ( P<0.01). 100 ng CD 3/KIF20A loaded T cells were observed under microscope, which obviously targeted KIF20A + pancreatic cancer PANC1 cells and had a strongest killing power. At the killing cells to targeting cells ratio of 20∶1 with 4-hour coculture, the killing rate of CD 3/KIF20A-vcDC-T cells on PANC1 cells was (88.6±2.6)%, which was significantly higher than (68.4±3.4)% and (39.2±2.1)% in the CD3/KIF20A-DC-T group and (39.2±2.1)% in the DC-T group, increasing by 20% and at lease 45%, respectively. Conclusions:DC-T cells loaded with CD 3/KIF20A antibody can significantly increase the killing rate of KIF20A positive pancreatic cancer PANC1 cells, and vitamin C intervention can further enhance the killing ability of antibody loaded T cells.