Transcriptional Profiling of a Cross-Protective Salmonella enterica serovar Typhimurium UK-1 dam Mutant Identifies a Set of Genes More Transcriptionally Active Compared to Wild-Type, and Stably Transcribed across Biologically

Vaccination with Salmonella enterica serovar Typhimurium lacking DNA adenine methyltransferase confers cross-protective immunity against multiple Salmonella serotypes. The mechanistic basis is thought to be associated with the de-repression of genes that are tightly regulated when transiting from one microenvironment to another. This de-repression provides a potential means for the production of a more highly expressed and stable antigenic repertoire capable of inducing cross-protective immune responses. To identify genes encoding proteins that may contribute to cross-protective immunity, we used a Salmonella Typhimurium DNA adenine methyltransferase mutant strain (UK-1 dam mutant) derived from the parental UK-1 strain, and assessed the transcriptional profile of the UK-1 dam mutant and UK-1 strain grown under conditions that simulate the intestinal or endosomal microenvironments encountered during the infective process.