Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/1995
Publication Date: N/A
Citation: N/A Interpretive Summary: Reticuloendotheliosis is a viral disease of chickens and turkeys and is particularly prevalent in Israel. At present there is no accepted method to control losses from this disease. This research addresses the possibility of vaccine development, and asks whether most field strains are of the same type, so that they might be protected by a single vaccine. The evirus that causes reticuloendotheliosis is composed of several proteins that cause the development of antibodies in infected animals. In this study which utilized specialized technologies to characterize the proteins of several virus strains, differences were found between different laboratory strains of the virus as had been previously reported. However, analysis of several field strains confirmed that the particular field strains used all belonged to the same type. This finding suggests that a single vaccine might protect against many or all of the naturally occurring gstrains in Israel.
Technical Abstract: The antigenic profiles of three REV prototype strains, CSV, SNV and REV-T and eight Israeli isolates were analyzed by SDS-PAGE and immunoblotting with convalescent chicken serum, three mAbs, 11A25, 11C237 and 11C100, a rabbit antiserum to REV-T whole virus (Cui et al., 1986) and a rabbit antiserum to REV-A p30 gag protein (Tsai et al., 1985). Under both reducing (+DTT) and non-reducing conditions of SDS-PAGE, a major immunodominant 75-100 kD band was seen to be shared by all strains examined. In contrast to the chicken serum that recognized both continuous and discontinuous epitopes on the 75-100 kD band of all the isolates, the mAbs and the two rabbit sera behaved otherwise. Only the DTT-resistant epitopes on the 75-100 kD band of REV-T were recognized by the rabbit antisera and the mAb 11C237, and only the DTT-labile epitopes of REV-T 75-100 KD antigen were detected by mAb 11C100. The two mAbs 11A25 and 11C237 detected discontinuous epitopes of all the strains except SNV, while the rabbit antisera recognized the discontinuous epitopes on the 75-100 kD band of all the 11 strains. The rabbit antisera and mAb 11C237 detected additional lower molecular weight proteins and the mAB 11C237 also detected three proteins of high molecular weight under non-reducing conditions only. The p30 antiserum detected the low molecular weight proteins demonstrating their gag gene-encoded identity. From these results we conclude that the major immunogen of REV is the 75-100 kD protein that contains both continuous and discontinuous epitopes. With this panel of antibodies the eight new isolates appeared to belong antigenically to REV subtype 3 (Chen et al., 1987).