Interleukin-8 Expression in Normal Nasal Epithelium and Its Modulation byInfection with Respiratory Syncytial Virus and Cytokines Tumor Necrosis Factor, Interleukin-1, and Interleukin-6

摘要

Inflammation in the nasal and airway tissue caused by allergens, microbialinfection and air pollution is likely to be regulated by inflammatory mediators produced by airway epithelial cells. We have therefore investigated the baseline expression of a number of cytokine genes known to be important inducers and modulators of inflammation, in freshly isolated human nasal epithelium. Cells were obtained by superficial scraping of turbinate tissue and cDNA for PCR amplification was reverse transcribed directly from lysates of 3,000-5,000 epithelial cells using random hexamers. Constitutive expression of high levels of IL-8 mRNA but undetectable levels of GM-CSF, IL-1 or TNF mRNA were found after PCR amplification of the cDNA. However, amplification of cytokine cDNAs reverse transcribed from purified RNA from pool scrapings of 8 subjects (approximately 100 x the amount of cDNA/PCR assay) revealed low level expression of TNF, IL-6 and GM-CSF, IL-beta but not of IL-1 alpha mRNA. Infection with respiratory syncytial virus (RSV) or stimulation of nasal epithelium for 4 hours with TNF or IL-1 in vitro, resulted in a 4 to 10 fold increase in IL-8 mRNA expression but not in the expression of detectable levels of mRNA for the other cytokines.