Expression of membrane-bound forms of TNF- and LT on HO-1 cells and the effects of anti–TNF- Ab on cytotoxicity. (A) HO-1 cells were stained by indirect immunofluorescence with rabbit anti–TNF- IgG, rabbit anti–LT- IgG, or rabbit anti–LT-β IgG, then with FITC-conjugated goat anti-rabbit IgG (shaded histograms). Control stainings were performed using normal rabbit IgG and FITC-conjugated goat anti-rabbit IgG (open histograms). (B) HO-1–induced lysis of DEK-CAN peptide-loaded autologous LCL (Fas^+/+ LCL) and Fas-deficient (Fas^−/−LCL) was examined in ⁵¹Cr release assays conducted over 4 hours at E:T ratios of 10:1, 5:1, and 2.5:1 in the presence of normal rabbit IgG or anti–TNF- rabbit IgG. The effect of Ab against TNF- was also examined using TNF-–dependent killer cells, MY-3.11, and L929 as TNF-–sensitive target cells.