Murine IFN-ab activity was measured using an L-929 cell line (provided by B. Beutler and Z. Jiang, Scripps Research institute, La Jolla) as described [18] Human IFN-ab bioactivity was measured using the HL116 cells from G. Uzé as described [101] . The contribution of IFN-a or IFN-b to the total IFN-ab activity was determined by pre-incubating plasma for 1 h with excess amounts of neutralizing anti-IFN-b antibody (Yamasa Corporation, Japan) or control antibody. Murine TNF-a was measured by a bioassay as described [95] . IL-6 was detected with an ELISA from Pharmingen BD. Human TNF-a was detected with an ELISA from R&D Biosystems. JNK/SAPK MAPKs were detected on immunoblots with antibodies detecting all or phosphorylated isophorms of the proteins (Cell Signaling). Zbp1/DAI and b-actin were detected on immunoblots with antibodies from Santa Cruz Biotechnology.