Detection of specific reticuloendotheliosis virus sequence and protein from REV-integrated fowlpox virus strains.

The detection is described of reticuloendotheliosis virus (REV) protein in tissue culture of chicken embryonated cells (CEFs) infected with field isolates of fowl poxvirus (FPV). By the polymerase chain reaction (PCR), five out of the six field isolates, but two out of the seven vaccine strains of FPV, were found to have had a 291 bp repeat sequence of REV-LTR integrated in their genomic DNA. An immunofluorescence (IF) method was employed using a monoclonal antibody (MAb) known to specify strain common envelope proteins for REV and allowed to detect the presence of a specific REV protein. The IF results indicate the localization of REV proteins in boundaries defined precisely within cells infected with these field strains of FPV carrying REV (FPV-REV). Furthermore, by immunoblotting (IB) using a chemiluminescent detection kit, the REV protein reacted specifically with the MAb and had a relative molecular mass (RMM) of 62 kDa. The data have the potential to advance substantially the current understanding of the integrated REV in FPV strains; and the identification of a unique protein associated with variant forms of FPV will also offer great potential for identification of novel vaccine candidates for use in poultry against variant forms of FPV.