Predicting short peptide immunogenic B cell epitopes distinct in RHDV1 and RHDV2 of Oryctolagus cuniculus.

Rabbit haemorrhagic disease virus (RHDV) can be lethal to Oryctolagus cuniculus. There are 2 types of RHDV, namely RHDV1 and RHDV2, which share a similar protein sequence. The protein sequence of these viruses is similar to other caliciviruses, such as the European brown hare syndrome virus (EBHSV) and Australian rabbit calicivirus (RCV-A1). High homology in their protein sequence may lead to the antibody's cross-reactivity to different antigens from these viruses. To design a short peptide synthetic epitope for diagnostic purposes, this study predicts 12 amino acid long immunogenic epitopes unique to RHDV1 and RHDV2. The protein sequences of RHDV1 and RHDV2 were mapped for possible epitopes. The identified epitopes, which were at least 12 amino acid long, were evaluated for antigenicity, hydrophilicity, and surface accessibility. The peptide sequence of the qualified epitopes was aligned with the protein sequence of RHDV1, RHDV2, EBHSV, and RCV-A1. The results show that out of 64 potential epitopes in RHDV1 and 67 varying length epitopes of RHDV2, only 31 and 32 12 amino acid long epitopes in RHDV1 and RHDV2, respectively, have desirable antigenic properties. Only three 12 continuous epitopes from each type of RHDV can distinguish them from each other. Among these 3 candidate short peptide epitopes, only SYPGNNATNVLQ in RHDV1 and VPSNPQPTTTTS in RHDV2 may differ from EBHSV and RCV-A1. These findings suggest that the unique immunogenic epitopes of RHDV1 and RHDV2 may potentially impact the development of diagnostic assays and vaccines specific to the different types of RHDV. [ABSTRACT FROM AUTHOR]