TNF and pulmonary emphysema: Previous studies have demonstrated that C57BL/6J mice responded to CS exposure with accelerated development of emphysema [1], [2], [3], [4], [5] while those of the strain 129S2/SvHsd, which produce low levels of tumor necrosis factor-alpha (TNF-α), were resistant to lung inflammation and oxidant responses to CS exposure [4], [5] showing no inflammatory response to smoke at 24 h [6].