Effects Of CTLs On Tumor Cells Killing Mediated By Different Antigen Loaded Dendritic Cells

Immunotherapy is a new method for cancer treatment besides other methods.such as operation, irradiation and chemotherapy.It is more and more mature and safety,but it's difficult to improve the treatment efficiency to reduce relapse rates and avoid all kinds of complications which are the most important study components in tumor immunotherapy. Dendritic cell(DC) is the most powerful antigen presenting cell(APC) so far which can activate naive T cell.It can not only activate immunity of autologous to attack tumor cells,but also is helpful to allogenic body. Immunotherapies with DCs to cure tumors are used in clinical fields now. Since it is difficult to obtain tumor cells from many patients and those relapsed,it is hard to develop immunotherapies with DCs efficiently and widely. But RNA can be amplificated in vitro,so we can solve the problem by transfecting RNA through liposome.Would it influence the differentiation and function of DC? How about the effect of kill tumor cells compare to other methods?It is the question that we want to know.In part I ,we used peripheral blood stem cell as precursor to induce DC differentiation and maturation.In the course we employed IL-4, GM-CSF and TNF-a.Two methods of loading antigen to DCs was used,one is freeze-melt,the other is transfection.DCs were idetificated by means of morphology and immune phenotype of cells.In part II ,we separated T cells from peripheral blood through Nylon column,and co-cultured with dendritic cells to induce CTLs. Effects of CTLs kill tumors were assayed by lactic dehydrogenase method and showed differences of the two methods.In the culture,by microscopy we observed that suspend cells became more and cell became augmentation. After 2 weeks,DCs loaded with antigen or not had typical form, and surface of the cells had many processes by scanning electron microscope. Atthe meantime, by flow cytometry cells were detected high expression of CD83,CD1a, CD80 and CD86. Moreover,there is no difference between DCs loaded with antigen and notloaded about the percentage of CD83 and CD1a.It showed that DCs loaded with antigen had no influence to the differentiation and maturation.We also observed that the percentage of the CD8+ cells was higher in the T cells which were activated by DC loaded with antigen than those were activated by DC not loaded with antigen.Compare CTLs were activated by DC transfected with RNA abstracted from tumor cells to CTLS were activated by DC loaded with freeze-melt tumor cells,the former was more efficiency in the assay of kill tumor cells.Furthermore,the former needed less tumor cells than the latter.We concluded that DC transfected with RNA abstracted from tumor cells had no influence on differentiaton and function. CTLs were activated by DC transfected with RNA abstracted from tumor cells is more efficiency in kill tumor cells than CTLS were activated by DC loaded with freeze-melt tumor cells,and the former needed less tumor cells.