Comparison of abilities of Salmonella enterica serovar typhimurium aroA aroD and aroA htrA mutants to act as live vectors

We compared the ability of Salmonella enterica serovar Typhimurium SL1344 aroA aroD (BRD509) and aroA htrA (BRD807) mutants to act as live vectors for delivery of fragment C of tetanus toxin (FrgC). FrgC was expressed in these strains from either pTETnir15 or pTEThtrA1. BRD509FrgC(+) strains elicited similar to 2-log-higher serum anti-FrgC antibody titers than BRD807FrgC(+) strains. All mice immunized with BRD807pTEThtrA1, BRD509pTEThtrA1, and BRD509pTETnir15 (but not BRD807pTETnir15) were protected against tetanus.