INTRAVENOUS HELICOBACTER-PYLORI INDUCES LOW-LEVELS OF TNF-ALPHA AND IL-1-ALPHA IN A MURINE MODEL

A murine model for testing cytokine production stimulated by Helicobac ter pylori is described. H. pylori induced significantly lower levels of TNF-alpha and IL-1 alpha compared to Escherichia coli or Pseudomona s aeruginosa when injected intravenously. The mean TNF-alpha concentra tion in serum during 6 h after stimulation with N. pylori was 0.2 ng/m l, whereas E. coli induced 4.7 ng/ml and P aeruginosa 6.0 ng/ml. This was not explained by rapid elimination of H. pylori i as bacteria were present for at least 3 h in the blood. The difference in cytokine ind uction may be a reflection of the bacteria's different biological qual ities. E. coli and P aeruginosa are both capable of causing systemic d isease, whereas H. pylori causes only a local, often low grade, inflam mation in the gastric mucosa.