OBJECTIVESTo evaluate the effects of K562-dendritic cell (DC) and Raji-DC fusion vaccines on the cytotoxicity of cord blood (CB) derived cytokine-induced killer/natural killer (CIK/NK) cells.

METHODSDC and CIK/NK cells were derived from CB mononuclear cells. CB-DC were fused with inactivated K562 or Raji cells by PEG to form K562 or Raji-DC fusion vaccine. The CIK/NK cells stimulated by different co-culture antigens were three groups: K562-DC or Raji-DC fusion vaccine group, inactivated K562 or Raji plus DC group, and CB-DC alone group. The cytotoxicity of CIK/NK cells stimulated by different co-culture antigens was measured by MTT test.

RESULTSAll the antigens used for stimulation could enhance the cytotoxicity of CB-CIK/NK cells, with no specificity difference. At 20:1 effector-target ratio, the cytolytic activities of K562-DC and Raji-DC fusion vaccine groups against Raji cells were (75.44 +/- 4.19)% and (81.33 +/- 4.18)% respectively (P < 0.05); and that of inactivated K562 + DC and Raji + DC group against Raji cells were (73.12 +/- 4.22)% and (80.49 +/- 4.27)%, respectively (P < 0.01). There was no significant difference in the cytotoxicity to K562 cells between the two fusion vaccine groups (P > 0.05). The cytotoxicity of CB-CIK/NK cells immunized by Raji cells was higher than that by K562 cells. In CIK/NK cells co-stimulated by the same tumor antigen, there was no significant difference in the cytotoxicity between DC fusion vaccine group and inactivated cells plus DC group to different tumor cells.

CONCLUSIONSThe cytotoxicity of CB-CIK/NK cells to tumor cells was not specific. There was no significant difference in the cytotoxic activity of CB-CIK/NK cells between the DC fusion vaccine group and inactivated cells plus DC group.