Reinforced cytotoxicity of lymphokine-activated killer cells toward glioma cells by transfection of the killer cells with the gamma-interferon gene.

Lymphokine-activated killer (LAK) cells generated from peripheral blood lymphocytes incubated with recombinant interleukin-2 were transfected with the human gamma-interferon (HuIFN-gamma) gene by means of liposomes having a positive charge on their surface. The cells secreted significant amounts of HuIFN-gamma (reaching more than 5 U/ml) into the culture medium. The HuIFN-gamma produced by the cells induced intercellular adhesion molecule-1 (ICAM-1) and enhanced the expression of Fas antigen on the surface of human glioma cells. Also, LAK cells transfected with HuIFN-gamma gene exhibited reinforcement of cytotoxicity toward human glioma cell lines (U251-MG and SK-MG-1). Furthermore, the reinforcement was significantly quenched by anti-ICAM-1 and/or anti-TNF-alpha monoclonal antibody.