Cytotoxic Effects of CML28 Specific T Cells on Acute Leukemia Cells In Vitro.

The antigen-specific cytotoxic T lymphocyte activated by antigen presenting cell is widely used in cell immunotherapy recently. CML28, which was screened from chronic myelogenous leukemia (CML) patients, was reported to be a specific tumour antigen and over-expressed on CML cells and acute leukemia cells. Therefore, CML28 could be a potential target for leukemia treatment. Dendritic cells (DC) are the most important antigen present cells, but it is hard to isolate and culture DCs for clinical use, which hampers the specific cell immunotherapy. Our investigation aimed to study the cytotoxic effects of CML28 specific T cells activated by artificial antigen presenting cells, on acute leukemia cells in vitro. Artificial antigen presenting cells were prepared by connecting CML28 to magnetic superbead that containing HLA-A2-Ig and B7-1 molecule. Mononuclear cells were isolated from the bone marrow or peripheral blood of healthy donors with positive HLA-A2. The artificial antigen-presenting cells were co-cultured with isolated mononuclear cells for four weeks. The activation and proliferation of CML28-specific T cells were measured by dimmer binding technique using flow cytometry. The cytotoxic effects of CML28-specific T cells on leukemia cells, which were isolated from leukemia patient, were evaluated by lactate dehydrogenase (LDH) releasing assay. Increased proportion of CML28-specific T cells was observed in artificial antigen-presenting group than in control group (29.27±3.54% vs 2.95±0.66%, p<0.05). For cytotoxic effects assay, significant higher killing efficiency was seen in artificial antigen-presenting group (41.47±4.23%vs3.56±0.71%, when the effector: target ration is 40:1, p<0.01). Therefore, we concluded that the artificial antigen presenting cells could mimic antigen presenting cells to induce specific T cell activation and proliferation, and cytotoxic effects on target cells, indicating that artificial antigen presenting cell-induced cytotocix T cells could be an option for leukemia treatment.