Fratelli M, Gagliardini V, Galli G, Gnocchi P, Ghiara P, Ghezzi P
Istituto di Richerche Farmacologiche Mario Negri, Milan, Italy.
Blood. 1995 Jun 15;85(12):3532-7.
We demonstrate here that EL4-6.1 cells, a mouse thymoma that expresses high levels of membrane interleukin (IL)-1 receptors, produce IL-1 beta as an autocrine regulatory factor. Endogenous IL-1 beta sustains both proliferation and apoptosis: during the exponential phase, it mainly promotes proliferation, while during the plateau phase of cell growth, it induces death by apoptosis. Additionally, we show that exogenous IL-1 beta added to EL4-6.1 cells in lag phase induces apoptosis in a portion of the cells and proliferation in the remaining cells. Therefore, IL-1 beta can exert two completely opposite effects on a single cell type, depending on the state of the target cell.
