IAI FigSearch
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Fernandez-Prada, C. M.
Right arrow Articles by Venkatesan, M. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Fernandez-Prada, C. M.
Right arrow Articles by Venkatesan, M. M.

 Previous Article  |  Next Article 

Infection and Immunity, June 2000, p. 3608-3619, Vol. 68, No. 6
0019-9567/00/$04.00+0

Shigella flexneri IpaH7.8 Facilitates Escape of Virulent Bacteria from the Endocytic Vacuoles of Mouse and Human Macrophages

Carmen M. Fernandez-Prada,1,2 David L. Hoover,2 Ben D. Tall,3 Antoinette B. Hartman,1 June Kopelowitz,1 and Malabi M. Venkatesan1,*

Department of Enteric Infections1 and Department of Bacterial Diseases,2 Division of Communicable Diseases and Immunology, Walter Reed Army Institute of Research, Washington, D.C. 20307, and Microbial Ecology Branch, CFSAN, Food and Drug Administration, Washington, D.C. 202043

Received 1 November 1999/Returned for modification 28 January 2000/Accepted 11 February 2000

The behavior of Shigella flexneri ipaH mutants was studied in human monocyte-derived macrophages (HMDM), in 1-day-old human monocytes, and in J774 mouse macrophage cell line. In HMDM, strain pWR700, an ipaH7.8 deletion mutant of S. flexneri 2a strain 2457T, behaved like the wild-type strain 2457T. This strain caused rapid host cell death by oncosis, and few bacterial CFU were recovered after incubation in the presence of gentamicin as previously described for 2457T-infected HMDM. However, analysis of bacterial compartmentalization within endocytic vacuoles with gentamicin and chloroquine indicated that more pWR700 than 2457T was present within the endocytic vacuoles of HMDM, suggesting that ipaH7.8 deletion mutant transited more slowly from the vacuoles to the cytoplasm. In contrast to findings with HMDM, CFU recovered from pWR700-infected mouse J774 cells were 2 to 3 logs higher than CFU from 2457T-infected J774 cells. These values exceeded CFU recovered after infection of J774 cells with plasmid-cured avirulent strain M4243A1. Incubation with gentamicin and chloroquine clearly showed that pWR700 within J774 cells was mostly present within the endocytic vacuoles. This distribution pattern was similar to that seen with M4243A1 and contrasted with the pattern seen with 2457T. Complementation of pWR700 with a recombinant clone expressing ipaH7.8 restored the intracellular distribution of bacteria to that seen with the wild-type strain. Strains with deletions in ipaH4.5 or ipaH9.8, however, behaved like 2457T in both HMDM and J774 cells. The distribution profile of pWR700 in 1-day-old monocytes was similar to that seen in J774 cells. Like infected J774 cells, 1-day-old human monocytes demonstrated apoptosis upon infection with virulent Shigella. These results suggest that a role of the ipaH7.8 gene product is to facilitate the escape of the virulent bacteria from the phagocytic vacuole of monocytes and macrophages.

* Corresponding author. Mailing address: Department of Enteric Infections, Division of Communicable Diseases and Immunology, Walter Reed Army Institute of Research, 503 Robert Grant Ave., Room 3S12, Washington, DC 20307. Phone: (301) 319-9764. Fax: (301) 319-9801. E-mail: malabi.venkatesan{at}na.amedd.army.mil.

Infection and Immunity, June 2000, p. 3608-3619, Vol. 68, No. 6
0019-9567/00/$04.00+0


This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2000 by the American Society for Microbiology. All rights reserved.