Low biological activity of Helicobacter pylori lipopolysaccharide.

Lipopolysaccharide from the gastroduodenal pathogen Helicobacter pylori was tested for its ability to induce mitogenicity in mouse spleen cells, pyrogenicity in rabbits, and toxic lethality in galactosamine-sensitized mice. Compared with those for enterobacterial lipopolysaccharide, mitogenicity and pyrogenicity were a thousand-fold lower and lethal toxicity was 500-fold lower. We suggest that the phosphorylation pattern and acylation in lipid A are responsible for the low biological activity.