The present study was designed to compare the tumour inhibitory effects of local therapy based on insertion of cloned IL-2, IL-4, or IL-6 genes into the genome of murine plasmacytoma X63-Ag8.653, followed by injection of the genetically modified cells to the vicinity of the parental plasmacytoma growing in syngeneic mice. It was also designed to investigate the effects of combined gene therapy with IL-2- and IL-6-producing plasmacytoma cells. It has been found that insertion of the IL-2 gene into the genome of X63-Ag8.653 cells can abrogate tumorigenicity of the transduced cells more effectively than insertion of the IL-4 or IL-6 gene. Peritumoral administration of the genetically modified plasmacytoma cells producing IL-6 (X63-h-IL-6) resulted in a therapeutic effect comparable with that of the IL-2-producing cells (X63-m-IL-2), whereas no substantial therapeutic effect of IL-4-producing cells (X63-m-IL4) was observed. The combined gene therapy with IL-2- and IL-6-producing cells did not give any additive or potentiated therapeutic effect.

Institute of Molecular Genetics Academy of Sciences of the Czech Republic Praha