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Identified virulence factors of Helicobacter: Adherence
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BabA
(blood group antigen binding adhesin)
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Related genes: babA/hopS;
babB/hopT;
Keywords: Adherence;
Characteristics:
 Two alleles: babA2 gene encodes the complete adhesin, whereas babA1 is defective due to the presence of a 10 bp repeat motif which results in the elimination of the start codon and the lack of Leb antigen-binding activity.
babA2-genopositive H. pylori usually coexists with other disease-related H. pylori virulence-factor genes, such as vacA s1 and cagA.
Mechanism:
Binds to H, Lewis b antigen, and related ABO antigens. These fucose-containing blood group antigens are found on red blood cells and in the gastrointestinal mucosa.
References:
 Ilver D, et al., 1998. Helicobacter pylori adhesin binding fucosylated histo-blood group antigens revealed by retagging. Science 279(5349):373-377.
Gerhard M, et al., 1999. Clinical relevance of the Helicobacter pylori gene for blood-group antigen-binding adhesin. Proc. Natl. Acad. Sci. USA. 96(22):12778-12783.
Pride DT, et al., 2001. Allelic Variation within Helicobacter pylori babA and babB. Infect. Immun. 69(2):1160-1171.
Rad R, et al., 2002. The Helicobacter pylori blood group antigen-binding adhesin facilitates bacterial colonization and augments a nonspecific immune response. J. Immunol. 168(6):3033-3041.
Zambon CF, et al., 2003. Helicobacter pylori babA2, cagA, and s1 vacA genes work synergistically in causing intestinal metaplasia. J. Clin. Pathol. 56(4):287-291.
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HopZ
(H. pylori outer membrane protein)
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Related genes: hopZ;
Keywords: Adherence;
Characteristics:
Regulated by slipped-strand repair mechanism (CT dinucleotide repeats in signal-peptide coding region).
Functions:
Involved in adhesion.
References:
Peck B, et al., 1999. Conservation, localization and expression of HopZ, a protein involved in adhesion of Helicobacter pylori. Nucleic. Acids. Res. 27(16):3325-3333.
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SabA
(sialic acid-binding adhesin)
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Related genes: sabA/hopP;
Keywords: Adherence;
Mechanism:
Mediates binding to the structurally related siayl-Lewis x/a antigen, allow more intimate but weaker adherence.
References:
Mahdavi J, et al., 2002. Helicobacter pylori SabA adhesin in persistent infection and chronic inflammation. Science 297(5581):573-578.
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INTERFACE
Bacteria
