[Activation effects of BCR/ABL antigen on CML T cells mediated by protein transduction domain].

AIM: To study the activation effect of BCR/ABL antigen on T cells from CML patients mediated by protein transduction domain (PTD). METHODS: The fused plasmid containing PTD gene and b3a2 bcr/abl gene of CML was constructed by genetic engineering technique and was expressed in E.coli. The PBMCs from CML patients were stimulated in-vitro with purified PTD-BCR/ABL antigen and then expression of the activation antigen CD25 on CD8(+) and CD4(+) T cells after stimulation was detected by flow cytometry (FCM). RESULTS: After stimulation with 100 mg/L of PTD-BCR/ABL antigen (final concentration) for 4 days in-vitro, CD8(+) T cells were activated in 5 of 10 CML patients and CD4(+) T cells were activated in 2 of 10 patients. Both CD8(+) and CD4(+) T cells were activated simultaneously in one of them. However, neither CD4(+) nor CD8(+) T cells was activated in BCR/ABL antigen stimulation group as control. CONCLUSION: Using a PTD-mediated antigen transduction system, exogenous BCR/ABL antigen can be transferred into APCs and be processed and presented onto surface of APCs to activate Ag-specific CD8(+) and CD4(+) T cells in-vitro. The strategy outlined in this paper may provide a new approach for priming Ag-specific CD8(+) and CD4(+) T cells in-vitro and immunotherapy of CML.

[Alteration of the Cell Cycle during the Differentiation of HL-60 Cells by Induction of Retinoic Acid]

To study the alteration of the cell cycle during the differentiation of human myeloid leukemia cell line HL-60 induced with all trans-retinoic acid (RA), the flow cytometry was used to assay the various phases of cell cycle in HL-60 cells treated with RA. The results showed: (1) S + G(2)/M phase proportion kept relative invariability during the 48 hours incubation of HL-60 cells with RA, however, the proportion alteration of S-phase cells was associated with the RA concentrations. At 10(-6) mol/L RA, the proportion of S-phase cells appeared a temporarily increasing peak followed by persistent decrease of S-phase proportion. At 10(-5) mol/L RA, S-phase cell proportion only appeared the persistent decreasing tendency. (2) Re-culture of HL-60 cells without RA showed the decrease of S + G(2)/M and S-phase cells was associated with the increase of differentiated cells, but not all HL-60 cells were triggered into differentiation at the same time. Once the cells start to differentiate, even if there is no RA presence, the HL-60 cells were still differentiated until maturation. In conclusion, HL-60 cells are able to differentate and maturate after exposure to RA for a period of time. S-phase proportion is related to the concentrations of RA. Once the cells start to differentiate, even if there is no RA presence, the HL-60 cells still differentiatiated until maturation.