Objective To study the effect of nontypeable Hemophilus influenzae(NTHi) strain ATCC49247 on proinflammatory cytokines expression of human A549 lung epithelial cell line. Methods Confluent A549 cells were co-incubated with NTHi, NTHi+Erythromycin(10 mg/L), NTHi+Gentamicin(100 mg/L), and NTHi+Dexamethasone(100 μmol/L),and nuclear factor kappa B(NF-κB) inhibitor primed cells were co-incubated with NTHi for 24 h. Then levels of interleukin-8（IL-8） and tumor necrosis factor-α(TNF-α) in the supernatant was assayed by enzyme-linked immunosorbent assay(ELISA) and the expression of intercellular adhesion molecule-1(ICAM-1) in cells was detected by immunohistochemistry staining. Results A549 cells were transformed and died after co-intubated with NTHi for 24 h. NTHi induced A549 cells to release significantly greater amounts of IL-8, which was inhibited by NF-κB inhibitor pyrrolidine dithiocarbamate（PDTC）. Incubating of A549 cells with NTHi significantly induced release of IL-8 and the expression of ICAM-1, which was blocked by erythromycin and dexamethasone and not by gentamicin. TNF-α was not detected in all circumstances. Conclusions NTHi can increase significantly the release and expression of proinflammatory cytokines through NF-κB pathway. Antibacterial drug erythromycin also has anti-inflammatory effect.
Objective To observe the genotype distribution of Haemophilus parainfluenzae from patients with acute exacerbations of chronic obstructive pulmonary disease ( AECOPD) and their effects on A549 cells. Methods 80 hospitalized patients with AECOPD in our hospital were enrolled. Haemophilus parainfluezae were collected by sputum culture and genotyped, then inoculated with cell line A549. IL-6 and IL-8 concentrations in the supernatant were detected and cell morphology was observed at different time points. Results The patients were divided into three groups according to their symptoms. 15 Haemophilus parainfuenzae strains were collected and the positive culture rate between type 1 and type 3 COPD patients were statistically different. The concentrations of IL-6 and IL-8 were both significantly higher than control and increased as time passed. 4 genotypes were got by random amplification of polymorphic DNA ( RAPD) . In RAPD Ⅲ group, the IL-8 concentration was higher at 12h and 24h than others. No morphologic change was found in the cells inoculated with Haemophilus parainfuenzae by microscope after fixing. Conclusions Positive culture rate of Haemophilus parainfuenzae was different in different COPD groups according to symptoms. Haemophilus parainfuenzae can stimulate a cytokine response in A549 cells, maybe one of the pathogens of AECOPD, especially the RAPDⅢ type. Haemophilus parainfuenzae is not an intracellular bacteria.