Single-chain variable fragments selected on the 57-76 p21Ras neutralising epitope from phage antibody libraries recognise the parental protein

Phage antibodies have been widely prospected as an alternative to the use o f monoclonal antibodies prepared by traditional means. Many monoclonal anti bodies prepared against peptides are able to recognise the native proteins from which they were derived. Here ne show that the same is also true for p hage antibodies. We have selected a number of single-chain variable fragmen ts (scFv) from a large phage scFv library against a peptide from the switch region II of p21Ras. This peptide is known to reside in a mobile area of t he native protein and is the epitope of a well characterised monoclonal ant ibody. Selected scFvs were able to recognise native p21Ras in both ELISA an d Western blots, indicating that peptides are also likely to be very useful in selecting from phage antibody libraries. (C) 1999 Federation of Europea n Biochemical Societies.