FIG. 2.

(a) Amount of beta interferon secreted at various times after infection with wild-type (WT) poliovirus and with 3A-2 mutant poliovirus. MG63 cells were infected at 20 PFU/cell, and the amounts of beta interferon were determined by ELISA in conjunction with a standard curve. Standard error from replicate experiments is shown. Amounts of IL-6 (b) and IL-8 (c) secreted from MG63 cells as a function of time after mock infection or infection with wild-type or 3A-2 mutant poliovirus was also determined by ELISA in conjunction with standard curves. Standard error from replicate experiments is shown. At later time points there was a decrease in the total amount of IL-6 and IL-8 in the medium, leading to highly variable measurements and suggesting that the IL-6 and IL-8 proteins are unstable (data not shown).