Cell culture RAW264.7 murine macrophage-like cells were purchased from the ATCC and cultured in Dulbecco's modified Eagle's medium (Mediatech Inc., Herndon, VA) supplemented with 10% fetal bovine serum (HyClone, Logan, UT) and 2 mM glutamine (GIBCO, Carlsbad, CA). Experiments were done in 24-well tissue culture plates (Becton Dickinson, Lincoln Park, NJ) with 1 × 10 6 cells per well.