B16F10 MURINE MELANOMA-CELLS EXPRESS INTERLEUKIN-2 AND A FUNCTIONAL INTERLEUKIN-2 RECEPTOR

In this study, we analyzed interleukin-2 (IL-2) and IL-2 receptor (IL- 2R) expression in murine B16F10 melanoma and studied the effect of rec ombinant IL-2 (rIL-2) on the proliferation of these cells. Flow cytome try analysis revealed the presence of the IL-2R ct subunit in B16F10 m elanoma, with a mean positivity rate of 30%. Using confocal microscopy , the expression of this chain could be visualized on the surface of B 16F10 cells and in intracellular compartments when the cells were perm eabilized with ethanol. In addition to the alpha subunit, the IL-2R be ta subunit was also expressed in B16F10 cells as shown by reverse tran scription and polymerase chain reaction analysis. The functionality of the IL-2R on B16F10 cells was shown by the fact that cell proliferati on increased dose-dependently with the addition of rIL-2 to the cultur e medium. We also detected expression of the IL-2 gene in B16F10 cells . In Northern blot assays, a typical band of 0.9 kb corresponding to I L-2 mRNA was observed, although supernatants from B16F10 cultures had no detectable IL-2 activity. Furthermore, the addition of neutralizing antibody (anti-IL2) to cell cultures had no effect on cell proliferat ion. From these results, we concluded that an IL-2 signalling system i s present in murine B16F10 melanoma cells and that IL-2 favors B16F10 cell proliferation, suggesting a role for this cytokine in the tumoral activity of these cells.