Interleukin-8 response in cells from the human urinary tract induced by lipopolysaccharides of Proteus mirabilis O3 and O18.
OBJECTIVE
Proteus mirabilis is a common pathogen associated mainly with complicated urinary tract infections and sometimes with septicemia. There is great serological diversity of the microorganism. While P. mirabilis O3 is commonly found in patients with infections, the serotype O18 rarely occurs. The O18 lipopolysaccharide contains a phosphocholine substitute, which makes it unique among Proteus strains. To explain different clinical significance of the strains we evaluated the biological activity of the lipopolysaccharides of P. mirabilis O3 and O18, as measured by interleukin-8 (IL-8) production.


METHODS
Three cell lines were used, namely uroepithelial cells, renal epithelial cells and monocytes. IL-8 production was determined on the protein and mRNA levels using enzyme-linked immunosorbent assay and real-time polymerase chain reaction, respectively, and CD14 expression on the cell surface was studied using flow cytometry.


RESULTS
Uroepithelial cells and monocytes reacted to lipopolysaccharides by higher IL-8 production compared with renal epithelial cells. Cell specific IL-8 response corresponded to the cell expression of CD14. Renal epithelial cells produced more IL-8 after stimulation with the phosphocholine rich lipopolysaccharide O18, although adding phosphocholine alone did not induce or increase IL-8 production.


CONCLUSIONS
Our data suggest that different cells within the human urinary tract have different roles during urinary tract infection. The biological activity and pathogenicity of P. mirabilis lipopolysaccharides might be determined by their specific chemical structure.
Chromek
Milan
M
Department of Clinical Microbiology, Karolinska Hospital, Stockholm, Sweden.
Stankowska
Dorota
D
Dadfar
Elham
E
Kaca
Wieslaw
W
Rabbani
Hodjattallah
H
Brauner
Annelie
A
D002460:Cell Line; D004847:Epithelial Cells / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D016209:Interleukin-8 / Q000276:immunology*; D007668:Kidney / Q000166:cytology / Q000276:immunology*; D018950:Lipopolysaccharide Receptors / Q000032:analysis; D008070:Lipopolysaccharides / Q000032:analysis / Q000276:immunology*; D009000:Monocytes / Q000276:immunology*; D019081:O Antigens / Q000276:immunology; D010767:Phosphorylcholine / Q000032:analysis / Q000276:immunology; D011513:Proteus mirabilis / Q000145:classification / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis; D001743:Urinary Bladder / Q000166:cytology / Q000276:immunology*
D016209:Interleukin-8; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D019081:O Antigens; D012333:RNA, Messenger; C430212:lipopolysaccharide, Proteus; D010767:Phosphorylcholine