IDENTIFICATION OF 3 HIGHLY ATTENUATED SALMONELLA-TYPHIMURIUM MUTANTS THAT ARE MORE IMMUNOGENIC AND PROTECTIVE IN MICE THAN A PROTOTYPICAL AROA MUTANT

A panel of Salmonella typhimurium 14028s mutants, which were previousl y shown to be highly attenuated in the BALB/c mouse model of infection , were analyzed for their potential as live Salmonella oral-vaccine ca ndidates. A prototypical aroA mutant was chosen as a basis of comparis on. From the panel of mutants initially chosen for this study, three m utants with comparable levels of attenuation elicited higher Salmonell a-specific serum immunoglobulin G (IgG) and/or mucosal secretory-IgA a ntibody titers than the aroA vaccine strain. The three mutants, CL288, CL401, and CL554, also elicited a better protective immune response t han the aroA control strain, after a single oral dose of 1 x 10(9) to 2 x 10(9) bacteria.