Designing of Chimeric Vaccine against Canine Distemper Virus Targeting Hemaglutanin Protein

The canine distemper virus is highly contagious and affects dogs' respiratory systems. The virus belongs to the paramyxoviridae family and order Mononegavirales. This class of viruses contains a negative-strand RNA. This virus also affects raccoons, foxes, and other animals. The current study aims to design a vaccine against the virus employing reverse vaccinology. The target candidate for the vaccine design is a surface protein called Hemagglutinin. Viral hemagglutinin protein sequences were retrieved from the Uniprot database, and conserved regions were identified. Possible B-cell epitope regions were identified using the ABCpred server. These epitopes were analyzed for allergenic and antigenic properties using the Allergen FP server and VaxiJen v2.0 server. The epitopes, which were antigenic and non-allergenic, were screened for T cell epitopes using NetMHC and NetMHC2 servers. The toxicity of the selected peptides was evaluated using the Toxinpred server. The epitopes were further screened for transmembrane helices and signal peptides employing TMHMM v. 2.0 and SignalP 4.1 servers, respectively. The epitopes were then checked for the parameters using the ProtParam tool. Finally, the solubility of the epitopes was determined using the SOLPro server. Using the selected epitopes, a chimeric vaccine construct was constructed with the peptides by linking the peptides with the GPGPG linker to the cholera toxin subunit B. The chimeric vaccine was modeled using the Robetta server, and codon optimization of the construct was performed using the JCAT tool.