Genetic variability of Helicobacter pylori complicates efforts to develop a vaccine

October 25, 2017, Ludwig Maximilian University of Munich
Genetic variability Helicobacter pylori of complicates efforts to develop a vaccine
Credit: Kateryna_Kon / fotolia.com

The bacterium Helicobacter pylori is responsible for one of the most prevalent infections in humans. The infection can give rise to a number of conditions ranging from gastritis to peptic or duodenal ulcers and ultimately to stomach cancer. Perhaps the most striking feature of Helicobacter is its genetic heterogeneity. Its mutability allows it to continuously adapt to the challenges presented by the acidic nature of its environment, allowing the bacterium to establish a persistent infection which, if untreated, can be lifelong. LMU microbiologist Sebastian Suerbaum and his colleagues have now shown that this genetic variability, which had already been observed in the chronic phase of the infection, actually becomes manifest very early on, although the mutation rate at this stage is no higher than that seen in the later phases of infection. The new findings are reported in the latest issue of the journal Gastroenterology.

Suerbaum holds the Chair of Medical Microbiology and Hospital Epidemiology at LMU's Max von Pettenkofer Institute (of which he is also a Director). His research focuses on the role of in mediating Helicobacter's ability to adapt and survive in human hosts. Up to now, little work has been done to assess the degree of bacterial heterogeneity in the period immediately after the initial infection, simply because the infection is normally diagnosed only after it has become chronic.

Suerbaum and his colleagues were able to track the bacterium's early evolution from the very beginning of the by working with samples obtained from a small cohort of human volunteers who had been experimentally infected in the course of a clinical trial designed to assess the effects of a . This experimental design enabled them to monitor, at the molecular level, the changes that the H. pylori genome undergoes as the pathogen adapts to conditions on the surface of the gastric epithelium: "Our study shows that bacterium's is very high from the very beginning. Mutations in genes for antigens present in the experimental vaccine can actually inhibit their production, effectively blunting the immune response. Other genetic changes trigger the synthesis and secretion of a number of bacterial virulence factors that later play a role in pathogenesis," Suerbaum explains.

There is currently no demonstrably effective vaccine against Helicobacter. "The pathogen's high level of genetic diversity poses a significant challenge for vaccine developers," says Suerbaum. "The results of our study have definite implications for the choice of antigens that will be used as the basis for future vaccines," he adds.

Explore further: H. pylori vaccine shows promise in mouse studies

More information: Sandra Nell et al. Genome and Methylome Variation in Helicobacter pylori With a cag Pathogenicity Island During Early Stages of Human Infection, Gastroenterology (2017). DOI: 10.1053/j.gastro.2017.10.014

Related Stories

H. pylori vaccine shows promise in mouse studies

December 19, 2013
Researchers from Southern Medical University in Guangdong, Guangzhou, China, have developed an oral vaccine against Helicobacter pylori, the bacteria responsible for peptic ulcers and some forms of gastric cancer, and have ...

Stomach bacterium damages human DNA

September 6, 2011
The stomach bacterium Helicobacter pylori is one of the biggest risk factors for the development of gastric cancer, the third most common cause of cancer-related deaths in the world. Molecular biologists from the University ...

Recommended for you

Researchers find infectious prions throughout eyes of patients with deadly sporadic Creutzfeldt-Jakob disease

November 20, 2018
By the time symptoms of sporadic Creutzfeldt-Jakob disease (sCJD) are typically discovered, death is looming and inevitable. But, in a new study, researchers at University of California San Diego School of Medicine with colleagues ...

Researchers a step closer to understanding how deadly bird flu virus takes hold in humans

November 19, 2018
New research has taken a step towards understanding how highly pathogenic influenza viruses such as deadly bird flu infect humans.

Infants born to obese mothers risk developing liver disease, obesity

November 16, 2018
Infant gut microbes altered by their mother's obesity can cause inflammation and other major changes within the baby, increasing the risk of obesity and non-alcoholic fatty liver disease later in life, according to researchers ...

New study shows NKT cell subsets play a large role in the advancement of NAFLD

November 16, 2018
Since 2015 it has been known that the gut microbiota could have a direct impact on nonalcoholic fatty liver disease (NAFLD), which affects up to 12% of adults and is a leading cause of chronic liver disease. In the November ...

Antibiotic prescribing influenced by team dynamics within hospitals

November 15, 2018
Antibiotic prescribing by doctors is influenced by team dynamics and cultures within hospitals.

Discovery suggests new route to fight infection, disease

November 14, 2018
New research reveals how a single protein interferes with the immune system when exposed to the bacterium that causes Legionnaires' disease, findings that could have broad implications for development of medicines to fight ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.