Heterogeneity among Helicobacter pylori strains in expression of the outer membrane protein BabA.
The BabA adhesin of Helicobacter pylori is an outer membrane protein that binds to the fucosylated Lewis b histo-blood group antigen on the surface of gastric epithelial cells. We screened a phage-displayed ScFv (single-chain fragment variable) recombinant antibody library for antibodies reactive with a recombinant BabA fragment and identified two such antibodies. Each antibody recognized an approximately 75-kDa protein present in wild-type H. pylori strain J99 but absent from an isogenic babA mutant strain. An immunoreactive BabA protein was detected by at least one of the antibodies in 18 (46%) of 39 different wild-type H. pylori strains and was detected more commonly in cagA-positive strains than in cagA-negative strains. Numerous amino acid polymorphisms were detected among BabA proteins expressed by different strains, with the greatest diversity occurring in the middle region of the proteins. Among the 18 strains that expressed a detectable BabA protein, there was considerable variation in the level of binding to Lewis b in vitro. Heterogeneity among H. pylori strains in expression of the BabA protein may be a factor that contributes to differing clinical outcomes among H. pylori-infected humans.
Hennig
Ewa E
EE
Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
Mernaugh
Ray
R
Edl
Jennifer
J
Cao
Ping
P
Cover
Timothy L
TL
D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D014644:Genetic Variation; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000145:classification / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D006801:Humans; D015151:Immunoblotting; D007135:Immunoglobulin Variable Region / Q000276:immunology; D007983:Lewis Blood Group Antigens / Q000378:metabolism; D008969:Molecular Sequence Data; D019151:Peptide Library; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D018829:Adhesins, Bacterial; C400429:BabA protein, Helicobacter pylori; D002352:Carrier Proteins; D007135:Immunoglobulin Variable Region; D007983:Lewis Blood Group Antigens; D019151:Peptide Library