THERAPEUTIC EFFECTS ON EXPERIMENTAL METASTATIC TUMOR-BEARING MICE BY VACCINATION WITH GM-CSF GENE-MODIFIED AND TUMOR ANTIGEN-PULSED MACROPHAGES

Macrophages, with potent cytotoxic and antigen-presenting activities, can be used in cancer treatment. The biological characteristics and an titumor effect of GM-CSF gene-modified and tumor antigen-pulsed macrop hages were investigated. The high levels of GM-CSF could be detected i n the supernatants oi macrophages after gene trans fer. The cytotoxici ty and the expression of MHC class II molecules of the gene-modified m acrophages increased significantly and the antigen-presenting ability was enhanced. The gene-modified macrophages were then pulsed with tumo r antigen and used to treat the experimental pulmonary metastastic mic e. The number of pulmonary metastases was reduced significantly and th e cytotoxicity of the CTL induced from the splenocytes of the rumor-be aring mice also increased. The results demonstrated that adenovirus-me diated GM-CSF gene transfer can activate macrophages to some extent an d GM-CSF gene-modified, antigen-pulsed macrophages may be a new type o f effective effector cells in the immunogene therapy of cancer.