title: Designed ankyrin repeat proteins as anti-idiotypic-binding molecules.
abstract: According to the network theory antibodies may act as antigens thus generating anti-idiotypic antibodies that can function as regulators of immune responses. Designed ankyrin repeat proteins (DARPins) are a new class of binding proteins and may serve as an alternative to antibodies. Selections from large DARPin libraries against the variable regions of a murine monoclonal anti-human IgE antibody, termed BSW17, yielded two highly specific anti-idiotypic DARPins both with high affinity. Their binding characteristics were comparable with these of a previously selected anti-idiotypic antibody. In vitro cell assays showed that the anti-idiotypic DARPins were able to inhibit the binding of BSW17 to cell-bound IgE and prevented BSW17 functional activity. These experiments demonstrate the possibility to isolate anti-idiotypic DARPins recognizing idiotypic determinants analogous to antibodies. In the future these DARPins may be further analyzed for their potential as putative vaccine candidates.
authors.affiliation: Institute of Immunology, Inselspital, 3010 Bern, Switzerland. Monique.vogel@iib.unibe.ch
authors.forename: Monique
authors.initials: M
authors.lastname: Vogel
authors.forename: Elsbeth
authors.initials: E
authors.lastname: Keller-Gautschi
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Baumann
authors.forename: Patrick
authors.initials: P
authors.lastname: Amstutz
authors.forename: Christine
authors.initials: C
authors.lastname: Ruf
authors.forename: Franz
authors.initials: F
authors.lastname: Kricek
authors.forename: Beda M
authors.initials: BM
authors.lastname: Stadler
mesh_terms: D000818:Animals; D017089:Ankyrin Repeat / Q000276:immunology*; D000888:Antibodies, Anti-Idiotypic / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D006801:Humans; D051379:Mice; D015202:Protein Engineering; D051381:Rats; D017455:Receptors, IgE / Q000235:genetics / Q000276:immunology / Q000378:metabolism