STRAIN-SPECIFIC RECOMBINANT ANTIBODIES TO POTATO-VIRUS-Y POTYVIRUS

Single chain Fv antibody fragments have been selected from a synthetic phage-antibody library following three and four rounds of affinity se lection with purified potato virus Y, common strain (PVYo). The select ed fragments were highly specific for PVY and detected seven out of ni ne isolates of PVYo whilst failing to detect three isolates of PVYN an d 12 isolates of PVYNTN. Nucleotide sequence of the scFv genes showed the variable heavy fragments belonged to the human VH4 family, whilst the variable light fragments belonged to the V lambda 1 family. The fr agments were used in ELISA to detect virus at concentrations of 50 ng/ ml in plant sap and in comparisons with commercially available PVY mon oclonal antibodies were shown to have similar limits of detection. Thi s is the first report of the selection of a scFv specific for a member of the potyviridae, and its use in detecting and differentiating stra ins of PVY in infected plant sap. The results highlight the potential of the technology for the selection of strain specific antibodies with an avidity equivalent to traditional monoclonal antibodies raised aga inst viral pathogens and their use for viral diagnosis. (C) 1998 Elsev ier Science B.V. All rights reserved.