Dimeric IL-2 induces rapid onset of cell death.

<p>(A, B) CellTox Green dye was added to cultured VSMC followed by increasing concentrations of dimeric IL-2 isolated from murine aortas (A) or EL4 media (B). Tissue culture plates were immediately placed in the microplate reader and excited at 485 nm per manufacturer's instructions. Cells were lysed, as a positive control, using a proprietary lysis buffer (Roche). In part A, 100 ng/ml and 50 ng/ml are significantly different than 0 ng/ml (p = 1×10⁻⁴ for each, by Dunnett's test for multiple comparisons). In part B, 20 ng/ml and 10 ng/ml are significantly different than 0 ng/ml (p = 1×10⁻⁴ for each, by the same analysis). (C) Normal rat tubular epithelial cells (NRK-52E) were cultured for 30 minutes with 20 ng/ml dimeric IL-2, 40 ng/ml monomeric IL-2, or PBS. Scale bar: 50 µm. Results are representative of 10 experiments.