Evaluation of the antitumor activity of the interleukin-12/pulse interleukin-2 combination

Interleukin-I2 (IL-12) is a potent immunoregulatory cytokine that may serve as a key link between nonspecific immune surveillance mechanisms and the induction of specific T lymphocyte-mediated immune responses. More specifically, IL-12 may enhance the production of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) by T lymphocytes and natural killer (NK) cells, and potentiate dependent effect or mechanisms including NK/lymphokine-activated killer (LAK) and cyto-toxic T lymphocyte (CTL) responses. Furthermore, a large body of evidence suggests that IL-12 may favor the development of T-helper type 1 (TH-1) versus T helper type 2 (TH-2) cells during an immune response, and more recent findings suggest that  a loss of responsiveness to IL-12 (as evidenced by intracellular signaling) may be an important characteristic of lymphocytes that have developed a TH-2 phenotype.