Interleukin (IL)-23 and
IL-27 have been recently identified as members of the
IL-12 heterodimeric
cytokine family. The
cytokines are released from activated dentritic cells and play a crucial role in cell-mediated immunity. Expression profiles of the
cytokines' receptors suggest that target cells of the
cytokines are distinct depending on T cell maturation and differentiation. We first examined whether murine colon
carcinoma cells (Colon 26) expressing
IL-27 (Colon 26/IL-27) could produce antitumor effects in syngeneic mice. The mice developed small Colon 26/IL-27
tumors and subsequently rejected them, whereas parent
tumors continued to grow. Since Colon 26/
IL-12 and Colon 26/IL-23 cells were also rejected in syngeneic mice, we then investigated the combinatory antitumor effects of the
cytokines. We inoculated Colon 26/
IL-12, Colon 26/IL-23, Colon 26/IL-27 cells or mixed populations of the
cytokine producers into one flank of the mice that simultaneously received parent
tumors in the other flank. The parent
tumor growth influenced by the
cytokine producers was similar to each other. Combinatory antitumor effects were not produced by the
cytokine producers and application of the
cytokines did not show any synergistic effects.