[In vitro proliferation of CD4(+)CD25(+) T cells from PBMCs of the chronic myelocytic leukemia patients and their inhibitory effect on CD4(+)CD25(-) T cells].

OBJECTIVE: To investigate the in vitro proliferation of CD4(+)CD25(+) T cells from the peripheral blood mononuclear cells (PBMCs) of the chronic myelocytic leukemia patients and the inhibitory effect on CD4(+)CD25(-) T cells. METHODS: Magnetic-activated cell sorting (MACS) was used to separate CD4(+)CD25(+) T and CD4(+)CD25(-) T cells from the PBMCs of patients with chronic myelocytic leukemia, and the purity and activity of CD4(+)CD25(+) T cells were analyzed with flow cytometry. After stimulation with anti-CD3 mAb, anti-CD28 mAb and recombinant human interleukin-2 (rhIL-2), the CD4(+)CD25(-) and CD4(+)CD25(+) T cells were cocultured to observe the inhibitory effect of CD4(+)CD25(+)T on CD4(+)CD25(-)T cells using MTT assay. RESULTS: After cell sorting, the purity of CD4(+)CD25(+)T cells from healthy control and chronic myelocytic leukemia patients were (84.93-/+2.55)% and (86.32-/+2.40)%, respectively, showing no significant difference between them (P>0.05). The activity of CD4(+)CD25(+) and CD4(+)CD25(-) T cells from healthy control and the leukemic patients was also comparable [(98.12-/+0.68)% vs (97.33-/+0.78)%, P>0.05). In the coculture, CD4(+)CD25(+) T cells obviously inhibited CD4(+)CD25(-) T cell proliferation in vitro, and the maximum inhibition occurred when CD4(+)CD25(+)T cells were cocultured with CD4(+)CD25(-)T cells at the ratio of 1:1. CONCLUSION: The MACS system can effectively isolate CD4(+)CD25(+) and CD4(+)CD25(-) T cells. CD4(+)CD25(+) T cells obviously inhibit the proliferation of CD4(+)CD25(-)T cells in vitro, and the effect displays an effector-target ratio relationship.