- Transduction of the IL-12 gene into mouse anti-tumor lymphocytes results in a profound increase in the ability of these lymphocytes to mediate tumor regression following administration to tumor bearing mice. These cells have a profound advantage in inducing anti-tumor responses because very few cells are needed and there is no requirement for the concomitant administration of interleukin-2 (IL-2) as is the case for conventional cell transfer immunotherapies.