The role of bronchial epithelial Dnmt3b in limiting Pseudomonas induced CXCL1 transcription in human epithelial cells in vitro was confirmed in Dnmt3bfl/flCc10Cre mice in vivo, in which enhanced CXCL1 mRNA levels in bronchial brushes (2 hours) associated with elevated CXCL1 levels in BALF early (6 hours) after infection. The gene discussed is DNMT3B; the disease is infection.