Interactions of TRIC agents with macrophages and BHK-21 cells observed by electron microscopy

Lawn, A. M.; Blyth, W. A.; Taverne, Janice

doi:10.1017/s0022172400046507

Cited by 56 publications

(36 citation statements)

References 12 publications

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“…Based upon the absence of the lysosomal enzyme acid phosphatase, the chlamydial inclusion has for some time been considered nonlysosomal in character (11,17,36). More recently, these observations have been confirmed and extended by the application of probes for various markers characterizing discrete steps in the pathway of maturation of endosomes to lysosomes (16,25,30,32).…”

Section: Discussionmentioning

confidence: 99%

Restricted Fusion of Chlamydia trachomatis Vesicles with Endocytic Compartments during the Initial Stages of Infection

Scidmore¹,

Fischer

Hackstadt³

2003

Infect Immun

146

137

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The chlamydial inclusion occupies a unique niche within the eukaryotic cell that does not interact with endocytic compartments but instead is fusogenic with a subset of sphingomyelin-containing exocytic vesicles. The Chlamydia trachomatis inclusion acquires these distinctive properties by as early as 2 h postinfection as demonstrated by the ability to acquire sphingomyelin, endogenously synthesized from 6{N-[(7-nitrobenzo-2-oxa-1,3-diazol-4-yl)amino]caproylsphingosine} (C 6 -NBD-ceramide). The molecular mechanisms involved in transformation of the properties and cellular interactions of the inclusion are unknown except that they require early chlamydial transcription and translation. Although the properties of the inclusion are established by 2 h postinfection, the degree of interaction with endocytic pathways during the brief interval before fusogenicity with an exocytic pathway is established is unknown. Using a combination of confocal and electron microscopy to localize endocytic and lysosomal markers in C. trachomatis infected cells during the early stages of infection, we demonstrate a lack of these markers within the inclusion membrane or lumen of the inclusion to conclude that the nascent chlamydial inclusion is minimally interactive with endosomal compartments during this interval early in infection. Even when prevented from modifying the properties of the inclusion by incubation in the presence of protein synthesis inhibitors, vesicles containing elementary bodies are very slow to acquire lysosomal characteristics. These results imply a two-stage mechanism for chlamydial avoidance of lysosomal fusion: (i) an initial phase of delayed maturation to lysosomes due to an intrinsic property of elementary bodies and (ii) an active modification of the vesicular interactions of the inclusion requiring chlamydial protein synthesis.

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Section: Discussionmentioning

confidence: 99%

Restricted Fusion of Chlamydia trachomatis Vesicles with Endocytic Compartments during the Initial Stages of Infection

Scidmore¹,

Fischer

Hackstadt³

2003

Infect Immun

146

137

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show abstract

“…Similar effects caused by bacterial endotoxins have been related to their action on lysosomes, with the subsequent release of lysosomal enzymes (Weissmann & Thomas, 1962). Thus it seemed likely that the toxic activity of TRIC agents might also be mediated through the cell's lysosomes, particularly in view of the contrast observed by electron microscopy between events occurring in macrophages and those in * BHK-21 cells that have ingested TRIC agents (Lawn, Blyth & Taverne, 1973); in macrophages the organisms entered lysosomes; but in BHK-21 cells, in which they multiply without inducing cytotoxic effects, the organisms developed outside the lysosomal system.…”

Section: Introductionmentioning

confidence: 92%

Interactions of TRIC agents with macrophages: effects on lysosomal enzymes of the cell

Taverne

Blyth

Ballard

1974

J. Hyg.

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“…The rate of chlamydial ingestion by non-professional phagocytes is nearly 100 times greater than that of other small particulates and has thus been termed parasite-specified (Byrne & Moulder, 1978). Internalized EBs or EB envelopes apparently avoid the host defence mechanism of phagolysosome fusion, whereas heat-denatured EBs or EB envelopes do not (Eissenberg et al, 1983;Friis, 1972;Lawn et al, 1973). These data suggest the presence of a protein component(s) in the EB envelope, possibly exposed at the surface, whose native structure is essential to the successful infection of host cells.…”

Section: Introductionmentioning

confidence: 99%

Detection of Surface-exposed Epitopes on Chlamydia trachomatis by Immune Electron Microscopy

et al. 1989

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The cell surfaces of two Chlamydia trachomatis serovars were explored by immune electron microscopy with monoclonal anti bodies that recognize a number of chlamydial outermembrane components. Species, subspecies and serovar-reactive epitopes on the major outermembrane protein (MOMP) of a lymphogranuloma venereum biovar strain, L2/434/Bu, and a trachoma biovar strain, F/UW-6/Cx, were exposed on the surfaces of both elementary bodies (EBs) and reticulate bodies (RBs). Three epitopes on MOMP were inaccessible on EBs and RBs of both strains. These included a genus-reactive, species-reactive, and a subspecies-reactive epitope. In contrast, genus-specific epitopes on lipopolysaccharide (LPS) were not detected on the EB surface, but were clearly expressed on RBs of both L2/434/Bu and F/UW-6/Cx chlamydiae. Antibodies specific for the 60 kDa and 12 kDa 'cysteine-rich' outer-membrane proteins did not react with surface epitopes on either EBs or RBs. These data provide evidence that MOMP is a major surface antigen of both morphological forms, whereas some portions of the LPS molecule are exposed on the RB surface but become inaccessible to antibody after conversion to the infectious EB form.

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Interactions of TRIC agents with macrophages and BHK-21 cells observed by electron microscopy

Cited by 56 publications

References 12 publications

Restricted Fusion of Chlamydia trachomatis Vesicles with Endocytic Compartments during the Initial Stages of Infection

Restricted Fusion of Chlamydia trachomatis Vesicles with Endocytic Compartments during the Initial Stages of Infection

Interactions of TRIC agents with macrophages: effects on lysosomal enzymes of the cell

Detection of Surface-exposed Epitopes on Chlamydia trachomatis by Immune Electron Microscopy

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