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Helicobacter pylori expresses a complex surface carbohydrate, Lewis X
1Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada.
Infection and Immunity
|December 1, 1995
Summary
Helicobacter pylori expresses Lewis X (Lex) on its surface, mimicking human antigens. This molecular mimicry may explain immune evasion in infected individuals.
Area of Science:
- Microbiology
- Immunology
- Glycobiology
Background:
- Helicobacter pylori is a significant human pathogen.
- Understanding bacterial surface antigens is crucial for immune response studies.
Purpose of the Study:
- To investigate the presence and significance of Lewis X (Lex) antigen expression on Helicobacter pylori.
- To explore the role of Lex expression in H. pylori immune evasion.
Main Methods:
- Immunoelectron microscopy and ELISA were used to detect Lex expression on H. pylori cells.
- Immunoblots were performed on lipopolysaccharide fractions.
- Serum immunoglobulin binding assays were conducted.
Main Results:
- Monoclonal antibodies specific for Lex strongly reacted with H. pylori cells, including coccoid forms.
- Lex structures were localized to membrane fractions and associated with lipopolysaccharides.
- Host immunoglobulins in infected individuals blocked Lex MAb binding, indicating an immune response to Lex.
Conclusions:
- Helicobacter pylori expresses Lex, a structure that mimics human oncofetal antigens.
- This molecular mimicry may contribute to H. pylori's ability to evade the host immune response, potentially downregulating T-cell activity.