Rapid identification of a tobacco mosaic virus epitope by using a coat protein gene-fragment-pVIII fusion library
This study describes the identification of the epitope recognized by the tobacco mosaic virus (TMV) coat protein (CP)-specific monoclonal antibody 29 (MAb29) by displaying a CP gene-fragment library on pVIII of filamentous phage M13. More than 80 per cent of the clones isolated after one round of panning bound specifically to MAb29. DNA sequencing of ten randomly chosen MAb29-specific clones and subsequent sequence comparison revealed a common seven amino acid epitope (ELIRGTG) representing amino acids 131-137 of the TMV CP. The reactivity of MAb29 in competition ELISA towards glutathione S-transferase fused to this epitope was stronger than that towards full-length wild-type TMV CP, confirming the epitope sequence determined by gene-fragment phage display. This demonstrated that gene-fragment libraries displayed on the phage surface as fusion proteins with the filamentous bacteriophage gene VIII are useful tools for rapid identification of linear epitopes recognized by MAbs.