Construction of aromatic dependent Shigella flexneri 2a live vaccine candidate strains: deletion mutations in the aroA and the aroD genes.
Live Shigella flexneri 2a vaccine candidate strains with deletion mutations in the aro genes were constructed. Tn10-generated auxotrophic mutations were transduced from Escherichia coli to S. flexneri 2a with bacteriophage P1CmCts. The tetracycline-sensitive derivatives of Tn10 mutants obtained were selected on Bochner's medium and checked by DNA-DNA hybridization using aroA and aroD gene specific probes. The vaccine candidate strains were tested to assess the efficacy of protection in guinea-pig conjunctival epithelia (Sereny test). The strains did not cause keratoconjunctivitis and exhibited significant protection in the challenge experiments. A candidate vaccine strain (delta aroD) showed 100% protection against 10(7) c.f.u. of wild type strain in the immunized guinea-pigs.
Verma
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Karolinska Institute, Dept. Clinical Bacteriology, Huddinge Hospital, Sweden.
Lindberg
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AA
D000818:Animals; D001428:Bacterial Vaccines / Q000302:isolation & purification* / Q000627:therapeutic use; D002872:Chromosome Deletion; D004405:Dysentery, Bacillary / Q000517:prevention & control; D005260:Female; D006168:Guinea Pigs; D007114:Immunization; D009154:Mutation; D012763:Shigella flexneri / Q000235:genetics / Q000276:immunology*
D001428:Bacterial Vaccines