title: Auxotrophic Salmonella typhi as live vaccine.
abstract: Salmonella typhi 541Ty has deletions at aroA and purA, causing requirement for aromatic metabolites (including p-aminobenzoate) and for adenine. None of 36 volunteers who drank 10(8) to 10(10) bacteria of 541Ty or its Vi-negative mutant 543Ty showed any adverse effect; all gave evidence of cellular immune response but only a few had serum titre increases. S. typhimurium experiments (at the Wellcome Research Laboratories and at Stanford) show that adenine requirement may reduce both bacterial survival in mouse tissues and live-vaccine efficacy. S. typhi attenuated only by block(s) in aromatic biosynthesis may be more effective as oral-route live vaccine.
authors.affiliation: Department of Medical Microbiology, Stanford University School of Medicine, CA 94305-5402.
authors.forename: B A
authors.initials: BA
authors.lastname: Stocker
mesh_terms: D010129:4-Aminobenzoic Acid / Q000096:biosynthesis; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D001428:Bacterial Vaccines / Q000302:isolation & purification*; D005544:Forecasting; D014644:Genetic Variation; D006801:Humans; D062385:Hydroxybenzoates / Q000096:biosynthesis; D007111:Immunity, Cellular; D051379:Mice; D012485:Salmonella typhi / Q000276:immunology* / Q000378:metabolism; D014613:Vaccines, Attenuated / Q000302:isolation & purification
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D062385:Hydroxybenzoates; D014613:Vaccines, Attenuated; C009135:2,3-dihydroxybenzoic acid; D010129:4-Aminobenzoic Acid