Identification of novel B-cell epitope in gp85 of subgroup J avian leukosis virus and its application in diagnosis of disease

Abstract

Background: The gp85 is the main envelope protein of avian leukosis subgroup J (ALV-J) involved in virus neutralization. Here, we mapped the epitope in ALV-J gp85 by ELISA using synthetic peptides and developed epitope based diagnostic methods for ALV-J infection.

Results: The results revealed that monoclonal antibody (mAb) JE9 recognized ⁸³WDPQEL⁸⁸ motif, which was highly conserved in gp85 among different ALV-J strains by homology analysis. Moreover, after evaluation with two hundred and forty sera samples obtained from different chicken farms, the epitope-based peptide ELISA had much higher sensitivity than commercial ELISA kit for antibody detection of ALV-J.

Conclusions: A novel B-cell epitope recognized by the mAb JE9 was identified. The developed peptide-ELISA based on this novel B-cell epitope could be useful in laboratory viral diagnosis, routine surveillance in chicken farms, and also in understanding the pathogenesis of ALV-J.

Keywords: Antibody detection; Avian leukosis virus subgroup J; B-cell epitope mapping; Epitope-based peptide ELISA.

Fig. 1

Reactivity of the different synthetic peptides of gp85 with mAb JE9 using ELISA. The name of each column corresponds to the polypeptide in the Table 2

Fig. 2

Alignment of the epitopes motif with 51 ALV strains. The GenBank accession numbers of the ALV strains used are indicated in parentheses. The homologous sequences of different ALV strains corresponding to the identified epitope are boxed. Identical residues are indicated by “.”. “-” indicates that there was no corresponding amino acid at this position

Fig. 3

The result of partial serum samples evaluated with IFA. Panel a and b were negative and positive control respectively; Panel c to f were partial positive results by serum samples which were negative in IDEXX ELISA, but positive in peptide-ELISA