TNF and inflammation: We have previously shown that the predominant natural CLA isomer c9,t11-CLA reduces expression of the chemokine interleukin (IL)-8 in airway epithelial cells [7], inhibits IL-2 and tumor necrosis factor (TNF)-α in T-helper cells [8], and prevents experimentally induced airway inflammation in mice at least in part via a peroxisome proliferator-activated receptor gamma (PPARγ)-dependent mechanism [9].