Analysis of the induction of cytokine production by Pseudomonas aeruginosa pilin in the lung of mice

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It is well known that pili of Pseudomonas aeruginosa has important role for adherence to epithelial cell. Some studies have been revealed that pili induced IL-8 production from epithelial cell in vitro experiments. In this study, we investigated that the affects of intratracheal inoculation of pilin, which is a component protein of pili, in murine model. Pilin was extracted from SDS-PAGE gel after sucrose gradient centrifugation. Purified pilin of P.aeruginosa, BSA or lipopolysaccharide(LPS) were inoculated to 6 weeks old Balb/c mice intratracheally. The mice were sacrificed and performed bronchoalveolar lavage(BAL). BAL fluid were analysed for cell counts and cytokines(TNF-α, MIP-2, IL-4, IFN-γ) concentrations. Additionally, to investigate the critical epitope for infiltration of inflammatory cells, we sythesized thirteen peptides(residues 1-20,11-30,21-40,31-50,41-60,51-70,61-80,71-90,81-100,91-110,101-120,111-130,121-143 based on PAO-1 amino acids sequence) and inoculated these pept … More ides intratracheally followed by BAL for examination of WBC counts and cytokine concentration. White blood cells in BAL fluid whose mice were inoculated pilin increased after 6 hr inoculation compared with the BSA-inoculated control mice. Peak counts of WBC in BAL fluid of pilin inoculated at 72hr after inoculation. More than ninety percent of WBC were neutrophils. Intratracheal inoculation of pilin induced TNF-α and MIP-2 concentrations in BAL fluid compared with BSA inoculated group although there was no significant difference between pilin inoculated and BSA inoculated groups in the concentrations of IL-4 and IFN-γ in BAL fluid. On the other hand, all thirteen peptides did not affect any response of inflammatory cell and cytokine concentration in BAL fluid significantly although some peptides slightly induced neutrophils and TNF-α in BAL fluid. These findings suggest that pilin of P.aeruginosa is one of the important factors' for induction of inflammation in the P.aeruginosa respiratory infection. Less