Sensitized Dc Induced Ctl Specific Killing Of Hl60 Cells In Experimental Studies

Objective: Human tumor cells express a number of protein antigen that could be recognized by T-cells, thus providing potential targets for cancer immunotherapy. Dendri~ic cells (DCs) are rare leukocytes that are unique in their ability to present antigen to T-cell for both MHC class I and class II pathways. This property has prompted their recent application to therapeutic cancer vaccines. Isolated DCs loaded with tumor antigen in vitro and administered as a cellular vaccine have been formed to induce protecting and therapeutic anti-tumor immunity in experimental animals. But the clinical evaluation of DCs vaccination are still in its earliest phases, with a larger number of technology are awaiting in vivo assay before this approach is optimized. In this study, We have found that human DCs derived from cultured human peripheral blood mononuclear cells (PBMCs) were capable of presenting antigen to induce a HL6O protein-specific CTC response and killing the HL6O leukemia cells. Methods: DCs were derived from human PBMCs in the present of GM-CSF, TNF-a and IL-4. After S days-culturing, the morphologic characteristics of those cells were observed by means of light and electron microscopies. At the same time, HL6O cells were treated with citrate-phosphate buffer (pH3.3) at room temperature for 5 mm, and some HL6O cells were treated with frozen-melt for several times to get the tumor antigens peptides. Lowry's method was used to analyze the elution peptides concent. DCs pulsed with these peptides and also co-cultured with T cells to stimulate the proliferation of the specific CTL line producing which induce specific anti-HL6O leukemia cells response in vitro. SGC79O1 tumor cell line were taken as control in all of these assay. Result: In vitro expansion and purification of DCs with typical phenotype, morphology and function are critical to further studies, CTL and its supernate induced by DCs which stimulated by tumor antigen peptides (TAP) from HL6O cell line could selectively kill HL6O cells. At the same quentity (40.Ong/ml culture base), acid washing HL6O TAP expressed more powerful in killing HL6O cell line activity than frozen- melt TAP. The HL6O killed rate was 68.29%?1.37% and 24.60%? 4.40% respectively. The DCs which load acid washing HL6O TAP also stimulate specific CTL to kill the SGC79O1 tumor cell, but its killing activity was weak relatively. The rate was 45.95%?.47% and 16.09%? 4.98% respectively. Conclusion: 1. Frozen-melt and acid washing are effective methods to obtain tumor cells antigen peptide. 2. Lowry's method can be used estimate the HL6O cells antigen peptide. 3. 4Ong/ml TAP of HL6O cells can pulse DCs to active the specific CTL which induce efficient anti- HL60 leukemia cell line immune response, but these CTL express lower activity to kill the SGC79O1 cell line. 4. Compared with frozen-melt HL6O antigen peptides, acid washing tumor antigen show more powerful immune stimulating activity to DCs. 5. The differential types of tumor cells perhaps have some intersecting antigens.