Characterization of the Salmonella typhi Outer Membrane Protein C

Salmonella enterica serovar typhi, a Gram-negative food-borne pathogen, causes typhoid fever in humans. OmpC is an outer membrane porin of S. typhi expressed throughout the infection period. OmpC is potentially an attractive antigen for multivalent vaccines and diagnostic kit designs. In this study we combined in silico, in vitro and in vivo approaches to analyze various aspects of OmpC's antigenic properties. The conserved region, in addition to secondary and tertiary structures, and linear B cell epitopes, were predicted. A number of results obtained from in silico analyses were validated by experimental studies. OmpC was amplified, cloned and then expressed, with the recombinant protein then being purified. BALB/c mice were immunized by purified denatured OmpC. The titer of antibody was raised. Results of challenges with the pathogen revealed that the immunity is non-protective. Most of the theoretical and experimental results were in consensus. Introduced linear B cell epitopes can be employed for the design of diagnostic kits based on antigen-antibody interactions.