Differential expression of human beta defensin 2 and 3 in gastric mucosa of Helicobacter pylori-infected individuals.
BACKGROUND
Antimicrobial peptides are key players of initial innate immune responses to human pathogens. Two major representatives, the human beta defensin 2 and 3 (hBD2 and hBD3), are both known to be regulated by, and to affect viability of, Helicobacter pylori. Previously, it was demonstrated in vitro that H. pylori actively abrogates hBD3 expression during prolonged infections. Here, we comprehensively assessed hBD2 and hBD3 expression ex vivo in the gastric mucosa of healthy individuals.


METHODS
Twenty volunteers (H. pylori positive and H. pylori negative: n = 10) were enrolled. Helicobacter pylori-positive subjects underwent eradication therapy and repeated the protocol. Expression of both defensins was assessed by quantitative RT-PCR and ELISA, and correlated with histopathologic degree of gastritis.


RESULTS
hBD2 and hBD3 were found to be ubiquitously expressed in all three groups. In general, hBD2 levels were elevated in relation to H. pylori infection (up to 40-fold). This upregulation correlated with degree of gastritis in corpus and antrum. In contrast, hBD3 protein levels were significantly decreased, while corresponding mRNA amounts remained unchanged. Eradication therapy led to normalization of mucosal hBD2 expression, while hBD3 expression demonstrated high interindividual variations among individuals.


CONCLUSIONS
Both defensins are ubiquitously but differentially expressed in gastric mucosa in relation to H. pylori infection. Ex vivo data support the notion that H. pylori infection is associated with reduced hBD3 expression in chronic active gastritis.
Department of Molecular Biology, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117, Berlin, Germany.
Bianca
B
Bauer
Thomas
T
Wex
Doerthe
D
Kuester
Thomas
T
Meyer
Peter
P
Malfertheiner
D004797:Enzyme-Linked Immunosorbent Assay; D005753:Gastric Mucosa / Q000276:immunology / Q000473:pathology*; D020869:Gene Expression Profiling; D016481:Helicobacter Infections / Q000276:immunology / Q000473:pathology*; D016480:Helicobacter pylori / Q000276:immunology / Q000472:pathogenicity*; D006651:Histocytochemistry; D006801:Humans; D060888:Real-Time Polymerase Chain Reaction; D023083:beta-Defensins / Q000096:biosynthesis*
C422950:DEFB103A protein, human; C106641:DEFB4A protein, human; D023083:beta-Defensins