Treatment of malignant diseases using lectin-dependent lymphokine-activated killer cell-mediated cytotoxicity: Experimental research

Peripheral blood lymphocytes (PBL) possess lectin-dependent cellular cytotoxicity (LDCC) in the presence of various lectins. In this study we showed more potent LDCC could be induced in lymphokine-activated killer (LAK) cells. Among several lectins investigated in this study pokeweed mitogen (PWM) could give LAK cells most potent and broad spectrum LDCC when LAK cells were initially stimulated by PWM. Analysis of effector cells revealed that either PBL, CD3⁺CD4⁺, CD 3⁺CD 8⁺ cells or CD3-CD56⁺ cells expressed manifest cytotoxicity in the presence of lectins. Both anti-HLA class I and anti-HLA class II monoclonal antibodies did not inhibit LDCC at any concentrations applied. Taken together with the former result, HLA, CD 3, CD 8 or CD 56 molecules were not relevant to LDCC. Quality and quantity of binding sites were shown to be different between effector cells and target tumor cells revealed by FACS analysis using fluorescence conjugated PWM. Mechanism of LDCC partially associated with apoptotic cell death but without NO production by effector cells. These facts suggest that more potent immunotherapy of malignant diseases might be applicable using mechanism of LDCC.