Reinforced Cytotoxicity of Lymphokine‐activated Killer Cells toward Glioma Cells by Transfection of the Killer Cells with the γ‐Interferon Gene

Lymphokine‐activated killer (LAK) cells generated from peripheral blood lymphocytes incubated with recombinant interleukin‐2 were transfected with the human γ‐interferon (HuIFN‐γ) gene by means of liposomes having a positive charge on their surface. The cells secreted significant amounts of HuIFN‐γ (reaching more than 5 U/ml) into the culture medium. The HuIFN‐γ 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‐γ 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‐α monoclonal antibody.