Comparison of Helicobacter pylori and Escherichia coli in induction of TNF-alpha mRNA from human peripheral blood mononuclear cells.
OBJECTIVE
To investigate the difference between the abilities of Helicobacter pylori and Escherichia coli to induce expression of TNF-alpha in human peripheral blood mononuclear cells (PBMC).


METHODS
H pylori was isolated from gastric biopsy specimens. The mononuclear cells were isolated from human blood, cultured, and treated with either intact or sonicated E coli or H pylori, and mRNA expression for TNF-alpha was detected using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).


RESULTS
TNF-alpha mRNA expression levels were significantly higher in PBMCs stimulated with E coli compared to those stimulated with H pylori at the same number and identical conditions (P < .001). The results also suggest that sonicated bacteria were significantly (P < .001) less stimulatory for PBMCs than intact bacteria for both E coli and H pylori.


CONCLUSIONS
The ability of different H pylori strains isolated from biopsy samples to stimulate TNF-alpha from PBMCs was significantly lower than that of E coli. Sonicated bacteria, as compared to intact bacteria, was a very poor inducer of TNF-alpha mRNA expression, suggesting that the conformation of lipopolysaccharides (LPS) on the outer leaflet of the outer membrane is not totally conserved in sonicated bacteria.
Ahmadzadeh
E
E
Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, IR, Iran.
Zarkesh-Esfahani
H
H
Roghanian
R
R
Akbar
F Navab
FN
D000328:Adult; D002478:Cells, Cultured; D004926:Escherichia coli / Q000276:immunology*; D020869:Gene Expression Profiling; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D012329:RNA, Bacterial / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D012329:RNA, Bacterial; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha