Does BabA-positive Helicobacter pylori bind gastric epithelial Lewis b antigens and promote inflammation?

BabA is a major H. pylori adhesin with strong evidence for binding fucosylated Lewis b (Leᵇ) glycans on gastric epithelium. The complete claim is supported overall, although the step from adhesion to durable increases in bacterial burden is more qualified than the receptor-binding and inflammatory links.

Adhesion and colonization

• In isogenic H. pylori J99 experiments, babA disruption reduced Leᵇ binding from 235 ± 15 to 4 ± 1 OD units (P<0.001); disrupting babB did not impair binding. Complementation and binding-site variation likewise linked functional BabA to both Leᵇ recognition and gastric-tissue attachment.
• Human-Leᵇ transgenic mice showed enhanced epithelial adherence, supporting Leᵇ as an in vivo BabA receptor.
• This close mucosal attachment plausibly improves colonization fitness. However, rhesus macaques infected with babA knockout or Leᵇ-binding-site mutant organisms did not show a clear sustained reduction in gastric density, indicating compensation, adaptation, or contributions from other adhesins.

Inflammation and mechanism

• Human antral-biopsy studies associate babA2-positive strains, particularly when accompanied by cagA and vacA s1, with greater bacterial density, granulocytic infiltration, epithelial IL-8 expression, and histologic gastritis. Leᵇ-transgenic mice infected with BabA-positive organisms developed more severe gastritis and parietal-cell loss.
• BabA–Leᵇ anchoring can potentiate Cag pathogenicity-island type IV secretion-system delivery into epithelial cells, increasing proinflammatory signaling including IL-8.
• Established gastritis also increases epithelial sialylated Lewis antigens, potentially permitting altered adhesin–receptor interactions as infection and inflammation evolve.

Bottom line

• BabA-mediated binding to gastric Leᵇ is firmly established; it plausibly enhances colonization-related fitness and is linked to stronger local inflammation, partly through improved Cag-system effector delivery and IL-8 signaling. The magnitude and persistence of any independent BabA effect on total bacterial burden vary with bacterial adaptation and co-occurring virulence determinants.