Inhibition of acid secretion from parietal cells by non-human-infecting Helicobacter species: a factor in colonization of gastric mucosa?

Helicobacter pylori has been shown to produce a protein that inhibits acid secretion from parietal cells. We have examined other non-human-infecting Helicobacter species for this property by measuring the uptake of [14C]aminopyrine into rabbit parietal cells as an indirect assessment of acid secretion. Helicobacter felis and an isolate from a rhesus monkey were shown to inhibit acid secretion. Isolates of Helicobacter mustelae gave variable responses. Whole bacteria and cell-free sonicates impaired the uptake of [14C]aminopyrine. We also tested other bacteria, including Escherichia coli, Proteus vulgaris, Klebsiella oxytoca, and Campylobacter jejuni. As whole organisms, these control bacteria had little effect on acid secretion, but sonicates caused pronounced inhibition that was partially heat labile. Pronase treatment of H. pylori destroyed its inhibitory effect. These results suggest that most Helicobacter species, but not all isolates, are able to inhibit acid secretion from rabbit parietal cells. This property may be a factor in the establishment of long-term infection by these species.