Enterococcus faecalis bearing aggregation substance is resistant to killing by human neutrophils despite phagocytosis and neutrophil activation

Robert M. Rakita, Natalie N. Vanek, Karen Jacques-Palaz, Mee Mee, M. Michele Mariscalco, Gary M. Dunny, Mark Snuggs, W. Barry Van Winkle, Scott I. Simon

Research output: Contribution to journalArticle

102 Citations (Scopus)

Abstract

Enterococcus faecalis aggregation substance (AS) mediates efficient bacterium-bacterium contact to facilitate plasmid exchange as part of a bacterial sex pheromone system. We have previously determined that AS promotes direct, opsonin-independent binding of E. faecalis to human neutrophils (PMNs) via complement receptor type 3 and other receptors on the PMN surface. We have now examined the functional consequences of this bacterium-host cell interaction. AS-bearing E. faecalis was phagocytosed and internalized by PMNs, as determined by deconvolution fluorescence microscopy. However, these bacteria were not killed by PMNs, and internalized bacteria excluded propidium iodide, indicating intact bacterial membranes. Resistance to killing occurred despite activation of PMNs, as indicated by an increase in both functional and total surface Mac-1 expression, shedding of L- selectin, and an increase in PMN extracellular superoxide and phagosomal oxidant production. Deconvolution fluorescence microscopy also revealed that phagosomes containing AS-bearing bacteria were markedly larger than phagosomes containing opsonized E. faecalis, suggesting that some modification of phagosomal maturation may be involved in AS-induced resistance to killing. PMN phagosomal pH was significantly higher after ingestion of nonopsonized AS-bearing E. faecalis than after that of opsonized bacteria. The novel ability of AS to promote intracellular survival of E. faecalis inside PMNs suggests that AS may be a virulence factor used by strains of E. faecalis.

Original languageEnglish (US)
Pages (from-to)6067-6075
Number of pages9
JournalInfection and Immunity
Volume67
Issue number11
StatePublished - Nov 1999
Externally publishedYes

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Neutrophil Activation
Phagocytosis
Neutrophils
Bacteria
Enterococcus faecalis
Phagosomes
Fluorescence Microscopy
Macrophage-1 Antigen
Opsonin Proteins
Sex Attractants
L-Selectin
Propidium
Virulence Factors
Enterococcus faecalis aggregation substance
Oxidants
Cell Communication
Superoxides
Plasmids
Eating
Membranes

ASJC Scopus subject areas

  • Immunology

Cite this

Rakita, R. M., Vanek, N. N., Jacques-Palaz, K., Mee, M., Mariscalco, M. M., Dunny, G. M., ... Simon, S. I. (1999). Enterococcus faecalis bearing aggregation substance is resistant to killing by human neutrophils despite phagocytosis and neutrophil activation. Infection and Immunity, 67(11), 6067-6075.

Enterococcus faecalis bearing aggregation substance is resistant to killing by human neutrophils despite phagocytosis and neutrophil activation. / Rakita, Robert M.; Vanek, Natalie N.; Jacques-Palaz, Karen; Mee, Mee; Mariscalco, M. Michele; Dunny, Gary M.; Snuggs, Mark; Van Winkle, W. Barry; Simon, Scott I.

In: Infection and Immunity, Vol. 67, No. 11, 11.1999, p. 6067-6075.

Research output: Contribution to journalArticle

Rakita, RM, Vanek, NN, Jacques-Palaz, K, Mee, M, Mariscalco, MM, Dunny, GM, Snuggs, M, Van Winkle, WB & Simon, SI 1999, 'Enterococcus faecalis bearing aggregation substance is resistant to killing by human neutrophils despite phagocytosis and neutrophil activation', Infection and Immunity, vol. 67, no. 11, pp. 6067-6075.
Rakita, Robert M. ; Vanek, Natalie N. ; Jacques-Palaz, Karen ; Mee, Mee ; Mariscalco, M. Michele ; Dunny, Gary M. ; Snuggs, Mark ; Van Winkle, W. Barry ; Simon, Scott I. / Enterococcus faecalis bearing aggregation substance is resistant to killing by human neutrophils despite phagocytosis and neutrophil activation. In: Infection and Immunity. 1999 ; Vol. 67, No. 11. pp. 6067-6075.
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