B H Miller1, T M Shinnick. 1. Department of Microbiology and Immunology, Emory University School of Medicine and Division of AIDS, STD, and TB Laboratory Research, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. bhmiller@med.umich.edu
Abstract
BACKGROUND: The ability of Mycobacterium tuberculosis to survive and replicate in macrophages is crucial for the mycobacterium's ability to infect the host and cause tuberculosis. To identify Mycobacterium tuberculosis genes involved in survival in macrophages, a library of non-pathogenic Mycobacterium smegmatis bacteria, each carrying an individual integrated cosmid containing M. tuberculosis H37Rv genomic DNA, was passed through THP-1 human macrophages three times. RESULTS: Two of the clones recovered from this enrichment process, sur2 and sur3, exhibited significantly increased survival relative to wild-type bacteria. In coinfection experiments, the ratio of sur2 colonies to wild-type colonies was 1:1 at 0 hours but increased to 20:1 at 24 hours post phagocytosis. The ratio of sur3 colonies to wild-type colonies was 1:1 at 0 hours and 5:1 at 24 hours. The M. tuberculosis ORFs responsible for increased survival were shown to be Rv0365c for the sur2 clone and Rv2235 for the sur3 clone. These ORFs encode proteins with as-of-yet unknown functions. CONCLUSIONS: We identified two M. tuberculosis ORFs which may be involved in the ability of tubercle bacilli to survive in macrophages.
BACKGROUND: The ability of Mycobacterium tuberculosis to survive and replicate in macrophages is crucial for the mycobacterium's ability to infect the host and cause tuberculosis. To identify Mycobacterium tuberculosis genes involved in survival in macrophages, a library of non-pathogenic Mycobacterium smegmatis bacteria, each carrying an individual integrated cosmid containing M. tuberculosis H37Rv genomic DNA, was passed through THP-1human macrophages three times. RESULTS: Two of the clones recovered from this enrichment process, sur2 and sur3, exhibited significantly increased survival relative to wild-type bacteria. In coinfection experiments, the ratio of sur2 colonies to wild-type colonies was 1:1 at 0 hours but increased to 20:1 at 24 hours post phagocytosis. The ratio of sur3 colonies to wild-type colonies was 1:1 at 0 hours and 5:1 at 24 hours. The M. tuberculosis ORFs responsible for increased survival were shown to be Rv0365c for the sur2 clone and Rv2235 for the sur3 clone. These ORFs encode proteins with as-of-yet unknown functions. CONCLUSIONS: We identified two M. tuberculosis ORFs which may be involved in the ability of tubercle bacilli to survive in macrophages.
Authors: B Lagier; V Pelicic; D Lecossier; G Prod'hom; J Rauzier; C Guilhot; B Gicquel; A J Hance Journal: Mol Microbiol Date: 1998-07 Impact factor: 3.501
Authors: Z Zhu; J Yao; T Johns; K Fu; I De Bie; C Macmillan; A P Cuthbert; R F Newbold; J Wang; M Chevrette; G K Brown; R M Brown; E A Shoubridge Journal: Nat Genet Date: 1998-12 Impact factor: 38.330
Authors: S T Cole; R Brosch; J Parkhill; T Garnier; C Churcher; D Harris; S V Gordon; K Eiglmeier; S Gas; C E Barry; F Tekaia; K Badcock; D Basham; D Brown; T Chillingworth; R Connor; R Davies; K Devlin; T Feltwell; S Gentles; N Hamlin; S Holroyd; T Hornsby; K Jagels; A Krogh; J McLean; S Moule; L Murphy; K Oliver; J Osborne; M A Quail; M A Rajandream; J Rogers; S Rutter; K Seeger; J Skelton; R Squares; S Squares; J E Sulston; K Taylor; S Whitehead; B G Barrell Journal: Nature Date: 1998-06-11 Impact factor: 49.962