TNFSF10 and infection: Following infection with MCMV, surface TRAIL was induced to much higher levels on approximately half of the CD11bl°CD27− and a small percentage of CD11bl°CD27+ NK cells in the liver (5–6 fold increase in MFI in both subsets), while only very modest TRAIL induction (<2 fold) was seen on mature NK cells in this organ (Fig. 5C).