To investigate the specific antileukemia effect of dendritic cells (DC) pulsed with chronic myelogenous leukemic lysate antigen (CLA), dendritic cells from patients with chronic myelogenous leukemia (CML) were pulsed by CLA, and then cocultured with cytokine-induced killer (CIK) cells from CML patients (CIK + CLA-DC group). The cytotoxic activity in vitro was measured by using a lactate dehydrogenase release assay, and compared with CIK + DC, CIK and CIK + CLA groups. The results showed that under an effector-target ratio of 25:1, the cytotoxic activity of CIK + CLA-DC, CIK + DC, CIK and CIK + CLA groups against autologous CML cells was (68.8 +/- 14.2)%, (52.5 +/- 9.4)%, (20.6 +/- 7.5)% and (24.2 +/- 8.7)%, respectively. CIK + CLA-DC group displayed a strongest cytotoxic activity. When K562 and Raji cells acted as target cells and CIK as effectors, the cytotoxic activity against autologous CML cells in CIK + CLA-DC group (68.8 +/- 14.2)% was much higher than that against K562 cells (14.6 +/- 6.2)% and Raji cells (12.7 +/- 10.2)%, respectively. In conclusion, coculture of CIK cells with DC led to a significant increase in cytotoxic activity. The cytotoxicity could be further increased by DC pulse with CML cell lysate antigen, and cytotoxicity mediated by CML lysate antigen possess stronger specificity.