Vaccination with MCP-1 cDNA transfectant on human malignant glioma in nude mice induces migration of monocytes and NK cells to the tumor.

Recently, studies on vaccination with tumor cells genetically engineered to produce monocyte chemoattractant protein-1 (MCP-1) have provided some encouragement. These studies have shown infiltration of certain types of lymphocytes at the tumor site. However, natural killer (NK) cells have not yet been assessed. We obtained a human malignant glioma cell line producing human MCP-1 constitutively by transfection of MCP-1 cDNA. We then test the effect of vaccination with the MCP-1 transfectant on nude mice. Although vaccination with MCP-1 transfectant did not reduce the tumor in our study, it was associated with the infiltration of large numbers of NK cells and monocytes at the tumor site. The site of vaccination also showed large numbers of monocytes. NK cells were detected with anti-asialo GM1 antibody, and monocytes were detected immunohistochemically with F4/80. We assumed that infiltrating monocytes at the site of vaccination could promote the infiltration of monocytes and NK cells into the tumor site without T-cell mediated transduction because the host lacked T-cell function.