Poly-ICLC administration induces IFN-α in serum of treated mice. Peripheral blood samples were drawn from the tail vein at 0, 12, 24 and 48 hrs following i.m. poly-ICLC (50 μg) treatment. Serum IFN-α levels were determined using specific ELISA (Endogen, Rockford, IL). The average values of 3 mice in treated (■) or non-treated (▲) mice are depicted (n = 3/group). Systemic induction of IFN-α in serum peaked at 24 hrs following the poly-ICLC injection, whereas control mice with no poly-ICLC administration did not display any elevation in IFN-α levels.