Vaccine design of coronavirus spike (S) glycoprotein in chicken: immunoinformatics and computational approaches

BACKGROUND: Infectious bronchitis (IB) is a highly contagious respiratory disease in chickens and produces economic loss within the poultry industry. This disease is caused by a single stranded RNA virus belonging to Cronaviridae family. This study aimed to design a potential multi-epitopes vaccine against infectious bronchitis virus spike protein (S). Protein characterization was also performed for IBV spike protein. METHODS: The present study used various tools in Immune Epitope Database (IEDB) to predict conserved B and T cell epitopes against IBV spike (S) protein that may perform a significant role in provoking the resistance response to IBV infection. RESULTS: In B cell prediction methods, three epitopes ((1139)KKSSYY(1144), (1140)KSSYYT(1145), (1141)SSYYT(1145)) were selected as surface, linear and antigenic epitopes. Many MHCI and MHCII epitopes were predicted for IBV S protein. Among them (982)YYITARDMY(990) and (983)YITARDMYM(991) epitopes displayed high antigenicity, no allergenicity and no toxicity as well as great linkage with MHCI and MHCII alleles. Moreover, docking analysis of MHCI epitopes produced strong binding affinity with BF(2) alleles. CONCLUSION: Five conserved epitopes were expected from spike glycoprotein of IBV as the best B and T cell epitopes due to high antigenicity, no allergenicity and no toxicity. In addition, MHC epitopes showed great linkage with MHC alleles as well as strong interaction with BF2 alleles. These epitopes should be designed and incorporated and then tested as multi-epitope vaccine against IBV.