This Article Full Text Full Text (PDF) Supplemental material Other Versions of this Article: JB.00898-07v1 189/22/8224    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sano, G.-i. Articles by Matsuo, K. Search for Related Content PubMed PubMed Citation Articles by Sano, G.-i. Articles by Matsuo, K.

Flagella Facilitate Escape of Salmonella from Oncotic Macrophages ^,

Department of Microbiology and Immunology, School of Medicine, Keio University, Tokyo 160-8582, Japan,¹ Center for Biosciences and Informatics, School of Fundamental Science and Technology, Keio University, Kanagawa 223-8522, Japan,² Kitasato Institute for Life Sciences and Graduate School of Infection Control Sciences, Kitasato University, Tokyo 108-8641, Japan³

Received 8 June 2007/ Accepted 31 August 2007

The intracellular parasite Salmonella enterica serovar Typhimurium causes a typhoid-like systemic disease in mice. Whereas the survival of Salmonella in phagocytes is well understood, little has been documented about the exit of intracellular Salmonella from host cells. Here we report that in a population of infected macrophages Salmonella induces "oncosis," an irreversible progression to eukaryotic cell death characterized by swelling of the entire cell body. Oncotic macrophages (OnMs) are terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling negative and lack actin filaments (F-actin). The plasma membrane of OnMs filled with bacilli remains impermeable, and intracellular Salmonella bacilli move vigorously using flagella. Eventually, intracellular Salmonella bacilli intermittently exit host cells in a flagellum-dependent manner. These results suggest that induction of macrophage oncosis and intracellular accumulation of flagellated bacilli constitute a strategy whereby Salmonella escapes from host macrophages.

Published ahead of print on 14 September 2007.

Supplemental material for this article may be found at http://jb.asm.org/.