St. Louis, (Date) -- The bacterium that causes most peptic ulcers clings to the stomach wall by locking onto specific receptors on cells in the gastric lining. Collaborators in Sweden and the United States now have identified and isolated a bacterial protein that allows the microbe to cling.
"With this attachment protein in hand, it eventually should be possible to develop a vaccine against peptic ulcers and gastric cancer," says Thomas Borén, D.D.S., Ph.D., an assistant professor of oral biology at Umeå University in Sweden. Borén headed the research team, which published its findings in the Jan. 16 issue of Science.
When Borén was at Washington University School of Medicine in St. Louis in 1993, he discovered that Helicobacter pylori, the bacterium that infects the gastric lining, attaches to a carbohydrate called the Lewis b (Leb) blood group antigen. This antigen is found on the red blood cells of people with type O blood, but it also occurs on the gastric lining. "So the bacterium prefers to bind to receptors present in blood group O individuals," Borén says. "And we have found that this binding property is highly associated with H. pylori isolated from patients with ulcer disease."
Most of the world's population is infected with H. pylori, though the prevalence is higher in developing countries and in regions of poverty in the Western world. The bacterium probably is spread by unclean fingers and hands and contaminated food and water. More than one-third of Americans have this infection, and about 20 percent of them eventually develop peptic ulcer disease. Most gastric cancers also occur in people with current or past H. pylori infections. Although stomach cancer is rare in the United States, it is the most common male cancer in some parts of the world.