CXCL1 and infection: While P. aeruginosa infection resulted in significant induction of gene expression for interleukin (IL-)6, IL-8 and CXCL-1 in CFBE41o- cells (4 hours, Fig 1F–1H), there was no IL-8 or CXCL-1 gene induction in response to infection with P. histicola at any time point (Fig 1G and 1H).