Objective: To investigate the anti-chronic myeloid leukemia (CML) effect of cytotoxicity T lymphocytes (CTL) activated by dendritic cells (DC) pulsed with freeze thaw K562 lysates antigen.
Methods: DC were achieved by healthy donors peripheral blood monocytes which were induced by granulocyte-macrophage colony stimulating factor (GM-CSF) and IL-4. On the sixth day, these cells were collected. One part of them was used to prove that they were DC from morphology and phenotypes. The other part was pulsed with K562 lysates and the lysate-loaded DC were compared with immature DC from phenotypes. The expression of IL-12 and IFNgamma in supernatant, the mixed lymphocytes reaction and the specific cytotoxicity against leukemia cells were tested.
Results: Freeze thaw K562 lysate up-regulated the expression of various differentiation antigens of DC, such as CD(1a) (27.40 +/- 5.00)% vs (15.40 +/- 2.34)%, CD(80) (61.35 +/- 5.35)% vs (42.00 +/- 2.77)%, CD(83) (93.30 +/- 3.48)% vs (25.15 +/- 4.02)%, CD(86) (85.25 +/- 4.39)% vs (37.25 +/- 3.20)%, CD(40) (89.80 +/- 7.18)% vs (35.95 +/- 4.06)% and HLA-DR (49.50 +/- 5.45)% vs (17.15 +/- 3.61)%. Simultaneously, the expression of IL-12 rose after DC were loaded with tumor lysates after 24 hours (P < 0.05). The T cells from healthy donors and CML patients, proliferated by antigen loaded DC, could induce IFNgamma increase (P < 0.01). The proliferation of T cells had distinct relation with the time of antigen loaded with DC. These T cells had specific cytotoxicity against K562 and HLA partial matching CML cells.
Conclusions: DC pulsed with K562 lysates can stimulate T cells, and can keep high immunocompetence with specific cytotoxicity against K562.