Modulation of GRO-alpha and TNF-alpha production by peripheral blood mononuclear cells treated with killed Helicobacter pylori
Abstract number: p1185
Stassi G., Arena A., Cascio A., Iaria C., Calapai M., Gazzara D., Iannello D.
To evaluate the in vitro production of GRO-a and TNF-a by human peripheral blood mononuclear cells (PBMC) after stimulation with a suspension of Helicobacter pylori (Hp) (live, gentamicin-killed or a combination of killed and live). Gastric colonization by Hp is the major cause of chronic active gastritis and is often associated with duodenal and gastric ulceration, gastric carcinoma and mucosa-associated lymphoid tissue lymphoma. GRO-a seems to play an important role in recruiting and activating neutrophils in the gastric mucosa. TNF-a has been demonstrated to up regulate GRO-a production and, at high concentrations, to injure the gastric mucosa.
Materials and methods:
PBMC obtained from 5 healthy Hp-seronegative donors were cultured, and, after the stimulation with Hp, supernatants were analysed for the presence of TNF-a and GRO-a by immunoenzymatic methods. Hp isolated from a man with duodenal ulcer was cultured and suspended in PBS to a concentration of 109 bacteria/ml. The combined treatment was performed by adding to PBMC a suspension of gentamicin-killed hp (1.2 x 109 killed bacteria/ml) for 20 hours and after this period adding 1.2 x 109 lives Hp for further 24 h. After 44 h supernatants were harvested, centrifuged and stored at 80°C until cytokine assays.
To verify a possible correlation between TNF-a and GRO-a monoclonal antibodies (MAb) anti-TNF-a or anti-GRO-a were added to PBMC in all experimental conditions.
Data were analysed by one-way analysis of variance and by Student-Newman-Keuls test.
The amounts of TNF-a and GRO-a produced by PBMC after stimulation with live Hp were higher than those produced after stimulation with a combination of killed and live Hp and the latter were higher than those produced after stimulation with killed Hp. The addition of MAb anti-TNF-a to PBMC respectively treated with live, killed, or killed + live Hp, determined lower levels of GRO-a. These results demonstrate that the strong increase in GRO-a expression in PBMC infected with live Hp was, at least in part, dependent on the presence in supernatants of TNF-a. On the contrary, the addition of MAb anti-GRO-a did not influence the TNF-a release.
Our data show that pre-treatment with killed Hp can decrease inflammatory response during Hp infection. The hypothesis that killed Hp could influence the outcome of Hp infection requires further investigation.
|Session name:||XXIst ISTH Congress|
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