Zhang XY, Kurth A, Pauly D, Pauli G, Schade R, Ellerbrok H (2008): Application of hightitred IgY antibodies in orthopox virus diagnostics
J. Chin. Pharmaceut. Sci. 17 (3): 183-191.

Layer chickens were immunized with three species of inactivated orthopox virus (vaccinia virus, calpox virus and cowpox virus). Antibodies (IgY) were purified from egg yolks by improved polyethylene glycol precipitation. The development of IgY directed against orthopox virus antigens was followed by immunofluorescence assay, plaque reduction neutralization test and immunoelectron microscopy. Crossreactivity of two IgY antibodies with cells infected by the different strains of the pox viruses was also investigated by different methods (immunofluorescence assay, plaque reduction neutralization test and Western blot). Even in very high dilutions in immunofluorescence assay (titres up to 1:10 6 and 1:10 5 , respectively) and persisted on a plateau over 10 months after four booster injections, it was showed that antivaccinia virus IgY and anticalpox virus IgY were positive. Neutralizing activity and ultrastructural detection of antigen with goldlabelled antibodies were respectively observed in plaque reduction neutralization test and immunoelectron microscopy. Western blot analysis revealed specific binding of IgY to virus proteins. Thus, there was crossreactivity between different orthopox viruses. Finally, orthopox virusspecific IgY antibodies bounded magnetic beads (Dynabead™) were used to concentration of orthopox viruses. This study suggests that antipox virus IgY could serve as a useful tool for orthopox viruses diagnosis.