Nowadays, foodborne diseases are one of the main problems of the world that infect humans due to consumption of contaminated water or food. Typhoid fever is one of the major causes of illness and death in the world caused by Salmonella typhi. Vaccination is one of the most effective approaches in order to reduction of the disease risk. The main goal of this study is designing and characterization of antigenic determinants of a fusion protein originated from S.typhi usable as an effective vaccine. In this study, the outer membrane proteins of salmonella have been considered as candidates conferring protection against typhoid. Considering the evidence, OmpA, OmpF and OmpC proteins of salmonella applied in a multivalent vaccine design. Conserved motives of these proteins were selected using the CLC software and then their extracellular regions of these peptides were identified with PRED-TMBB server. Appropriate motives were combined for design of final fusion protein. Finally epitops of designed protein with high antigenic properties were identified using BCPREDS, Ellipro, ABCpred, EpiJen, NetCTL-1.2, CTLpred, TAPpred, ProPred and VaxiJen servers. Predicted designed protein in this study reached a very high scores for antigenic indexes. Encoding Genetic construction of this fusion protein could be applied for production of the recombinant OmpA.OmpF.OmpC derived fusion protein with effective antigenic properties as a new vaccine against S.typhi. Laboratory experiments and animal challenging analyses is ongoing. 

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