Selection of peptidic mimics of digoxin from phage-displayed peptide libraries by anti-digoxin antibodies

Citation
Wj. Ball et al., Selection of peptidic mimics of digoxin from phage-displayed peptide libraries by anti-digoxin antibodies, J MOL BIOL, 301(1), 2000, pp. 101-115
Citations number
52
Categorie Soggetti
Molecular Biology & Genetics
Journal title
JOURNAL OF MOLECULAR BIOLOGY
ISSN journal
00222836 → ACNP
Volume
301
Issue
1
Year of publication
2000
Pages
101 - 115
Database
ISI
SICI code
0022-2836(20000804)301:1<101:SOPMOD>2.0.ZU;2-T
Abstract
Since the initial report of the development of methodology to generate high -affinity digitalis-specific (digoxin) antibodies, these antibodies have pr oven extremely useful tools to monitor digoxin levels in digitalized patien ts and, as Fab fragments, to reverse toxic digoxin effects in life-threaten ing digoxin overdoses. These antibodies (both digoxin-specific and ouabain- specific) have been used extensively by investigators for the identificatio n and characterization of putative endogenous digitalis-like factors. In th is study, we used two well-characterized mouse anti-digoxin monoclonal anti bodies (mAbs), designated 26-10 and 45-20, as binding templates with which to select short bacteriophage-displayed (pIII protein inserted) peptides th at are capable of binding to these mAbs and mimicking the conformational st ructure of digoxin. Selective enrichment from two phage-displayed random pe ptide Libraries enabled us to isolate and identify distinct 15 and 26 amino acid residue peptide inserts that bind with high avidity and idiotypic spe cificity to the selecting mAbs. Among these displayed inserts a subset was identified whose mAb binding is inhibited by digoxin and whose correspondin g synthetic peptides inhibit phage binding. They, therefore, appear to bind at the mAbs digoxin-binding sites. These data provide the first clear evid ence that short polypeptides can serve as surrogates for the low molecular mass hapten digoxin. (C) 2000 Academic Press.