Monoclonal antibodies are the basis of various techniques used for antigen detection or characterization, and their use is specially recommended for the identification of viral strains involved in the etiology of infectious bronchitis outbreaks. These antibodies are homogeneous, highly specific and fully characterizable, allowing the improvement of immunological techniques detection and antigenic characterization of avian infectious bronchitis virus strains (IBV). A phage display library was used, which was prepared previously against the IBV vaccine strain (H120) for the selection of new scFv antibody fragments specific for heterologous IBV strains isolated from outbreaks in Brazil (IBVPR01, IBVPR05) and USA (SE-17). After three cycles of panning, a set of 15 scFv antibodies were expressed in phages and cross-reacted in ELISA with these three viral strains. Western-blotting analysis showed that two of the clones were expressing scFv specific for the nucleoprotein of these IBV strains, as well as to the recombinant form of this protein derived from M41. In conclusion, the recombinant fragments of monoclonal antibodies expressed in phage have a great potential for future use in immunodiagnostic techniques and to study the evolution of infectious bronchitis virus.
infectious bronchitis virus; monoclonal antibody; nucleoprotein; field strains; scFv
