ABSTRACT
Antitumor effect of combined transfer of suicide gene and cytokine gene was evaluated in the present study. Adenoviruses expressing E. coli. cytosine deaminase (AdCD) and adenoviruses expressing murine interleukin 2 (AdTL2) were used for the treatment of tumor-bearing mice. The mice were inoculated s. c. with FBL-3 leukemia cells and 3 days later received intratumoral injection of AdCD in the presence or absence of AdIL2 followed by intraperitoneal 5-fluorocytosine (5FC) administration. The results demonstrated that tumor-bearing mice treated with AdCD/5FC in combination with AdTL2 showed more .potent inhibition of tumor growth and survived much longer as compared with mice treated with AdCD/5FC, AdEL2, AdlacZ/5FC or PBS. It was illustrated that the tumor mass showed obvious necrosis and inflammatory cell infiltration, and more CD4+ and CD8+ T cells infiltrated into the tumor after combined therapy. The splenic NK and CTL activities increased significantly in mice after combined transfer of CD gene and EH gene. Our results demonstrated that combined transfer of suicide gene and IL-2 gene could inhibit the growth of established tumor in mice significantly and induce antitumor immunity of the host efficiently.
