Killing effect of costimulated activation of peripheral blood mononuclear cells with CD80 and CD28/CpG ODN on gastric cancerous cells MKN45 / 中国组织工程研究

ABSTRACT

BACKGROUND: Maintenance and activation of cascade reaction influence T cell proliferation or transformation into nonreactive state even apoptosis. B7 binding to CD28 effectively activates T cells in combination with T cell receptor pathway, and enhances T cell proliferative activity. OBJECTIVE: To investigate the costimulated activation of peripheral blood mononuclear cells (PBMC) with CD28 and CpG containing oligodeoxynucleotides (CpGODN) MoAb combined with CD80, and its killing effect on human gastric cancerous cell line MKN45 in vitro.METHODS: PBMCs were isolated by Ficoll density gradient centrifugation method, and cocultured with interleukin-2, CD28 and CpGODN MoAb for 1-5 days. MKN45 cells were divided into 4 culture conditions CD28/CpGODN, CD80 plus CD28/CpG ODN, CD80 alone, and blank control.The killing efficiency was measured by MTT method.The ultramicrostructure of cells was observed by electron microscope. Apoptosis was verified by a flow cytometery. RESULTS AND CONCLUSION: CD80 alone did not display killing effect on MKN45 cells. By MTT method, combination of costimulated activation of PBMC with CD28/CpGODN and CD80 showed enhanced killing effect compared with single therapy (P < 0.05), and the ratio of effector cell and target cell at 15 1 resulted in half killing efficiency. Electron microscope and flow cytometery verified necrotic or apoptotic cells after 24 hours exposure to costimulated activation. Compared with blank control group, CD80 alone elevated the apoptosis rate of MKN45 cells (P < 0.01). Results from the present study show that CD80 can elevate the killing effect of costimulated activation of PBMC with CD28/CpGODN on MKN45 cells in vitro.