Related Experiment Video
Updated: May 27, 2026

Gastric Mucosa Quantitative Polymerase Chain Reaction Analysis for Detecting Helicobacter pylori and Antibiotic Resistance
Published on: March 7, 2025
Genotypic and phenotypic variation of Lewis antigen expression in geographically diverse Helicobacter pylori isolates
Mary Ann Pohl1, William Zhang, Sunny N Shah
1Department of Medicine, New York University School of Medicine, New York, NY, USA. maryann.pohl@einstein.yu.edu
Background:
Helicobacter pylori are a persistent colonizer of the human gastric mucosa, which can lead to the development of peptic ulcer disease and gastric adenocarcinomas. However, H. pylori can asymptomatically colonize a host for years. One factor that has been hypothesized to contribute to such persistence is the production of Lewis (Le) antigens in the lipopolysaccharide layer of the bacterial outer membrane as a form of molecular mimicry, because humans also express these antigens on their gastric mucosa. Humans and H. pylori both are polymorphic for Le expression, which is driven in H. pylori by variation at the Le synthesis loci. In this report, we sought to characterize Le genotypic and phenotypic variation in geographically diverse H. pylori isolates.
Materials And Methods:
From patients undergoing endoscopy in 29 countries, we determined Le phenotypes of 78 H. pylori strains and performed genotyping of the galT and β-(1,3)galT loci in 113 H. pylori strains.
Results:
Le antigen phenotyping revealed a significant (p < .0001) association between type 1 (Le(a) and Le(b) ) expression and strains of East Asian origin. Genotyping revealed a significant correlation between strain origin and the size of the promoter region upstream of the Le synthesis gene, galT (p < .0001).
Conclusion:
These results indicate that the heterogeneity of human Le phenotypes is reflected in their H. pylori colonizing strains and suggest new loci that can be studied to assess the variation of Le expression.
Related Concept Videos
Genetic Variation
Genes exist in different versions called alleles, which...
Peptic Ulcer Disease III: Clinical Manifestations and Diagnostic Studies
Few clinical manifestations differentiate gastric ulcers from duodenal ulcers. Distinctions in the location, timing, and pain relief are crucial for healthcare providers in differentiating between gastric and duodenal ulcers during clinical assessments.
Gastritis II: Pathophysiology
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
Principles of Pharmacogenetics: Types of Genetic Variants
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
