Novel non-reverting shigella live vaccines

摘要: Live vaccines are provided and methods for preparing the live protection of a host from pathogenic microorganism. The prepared by introducing at least one modification in gene involved one, normally two, biosynthetic pathways involving production products which unlikely to be found disease susceptible host. results change cannot repaired single step, e.g. polynucleotide deletions inversions. Where aro suffers such change, resultant auxotrophic mutants require aromatic amino acids, p-aminobenzoic acid 2,3-dihydroxybenzoic or highly concentrated source absorbable iron. mutations have substantially reduced nonexistent virulence while retaining desired immunogenicity initiate immunogenic response. Various techniques can employed providing change. Salmonella typhimurium strain SL1479 was deposited ATCC on September 7, 1982 given Accession No. 39183; dublin SL1438 39184. typhi 531Ty November 21, 1984, granted 39926. Shigella flexneri SFL114 March 14, 1988 NO. 53755.