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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-11-17
pubmed:abstractText
Previously we have described studies on in vitro pentamer assembly of Escherichia coli (E. coli) derived heat-labile enterotoxin B subunit (EtxB) using conventional monoclonal antibodies (Amin et al., JBC 1995: 270, 20143-50 and Chung et al., JBC 2006: 281, 39465-70). To extend these studies further we have used phage-display to select single-chain Fragment variable (scFv) antibodies against different forms of the B-subunit. Two clones exhibiting strong and differential binding were chosen for detailed characterization. A comprehensive sequence analysis was performed to assign the framework and complementary-determining regions and a nonsense mutation present in one of these (scFv-B1.3.9) was corrected. Binding analysis showed that scFv-B1.3.9 bound in ELISA to both heat-denatured monomeric B-subunits (EtxB1) and also displayed cross-reactivity towards pentameric EtxB (EtxB5), although there was no reactivity towards monoganglioside (GM1) captured EtxB5. Another antibody (scFv-B5.2.14) had a different reactivity profile and, in ELISA, bound only to EtxB5 but not to EtxB1 or to EtxB5 captured via GM1. Surprisingly, in competition experiments, the assembled pentameric B-subunit inhibited binding of scFv-B5.2.14 to immobilized EtxB5 only weakly, whereas reduced, but not oxidized, monomeric EtxB1 was an efficient competitor. These results clearly demonstrate that B1.3.9 and B5.2.14 have different specificities for cryptic epitopes not accessible in the fully assembled GM1 bound pentameric form of EtxB. Taken together our results show that we were able to successfully isolate and characterize recombinant scFvs that differentially recognize diverse denatured forms or assembly intermediates of the heat-labile enterotoxin B subunit of E. coli.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-1759
pubmed:author
pubmed:issnType
Print
pubmed:day
31
pubmed:volume
339
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
115-23
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Phage-display derived single-chain fragment variable (scFv) antibodies recognizing conformational epitopes of Escherichia coli heat-labile enterotoxin B-subunit.
pubmed:affiliation
Royal College of Surgeons, Department of Surgery, Connolly Hospital, Blanchardstown, D15, Ireland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't