Title | Differential interaction with endocytic and exocytic pathways distinguish parasitophorous vacuoles of Coxiella burnetii and Chlamydia trachomatis. |
Publication Type | Journal Article |
Year of Publication | 1996 |
Authors | Heinzen, RA, Scidmore, MA, Rockey, DD, Hackstadt, T |
Journal | Infect Immun |
Volume | 64 |
Issue | 3 |
Pagination | 796-809 |
Date Published | 1996 Mar |
ISSN | 0019-9567 |
Keywords | Animals, Antigens, CD, Chlamydia trachomatis, Chlorocebus aethiops, Coxiella burnetii, Endocytosis, Exocytosis, Humans, Lysosome-Associated Membrane Glycoproteins, Lysosomes, Membrane Glycoproteins, Mice, Rabbits, Sphingolipids, Vacuoles, Vero Cells |
Abstract | Coxiella burnetii and Chlamydia trachomatis are bacterial obligate intracellular parasites that occupy distinct vacuolar niches within eucaryotic host cells. We have employed immunofluorescence, cytochemistry, fluorescent vital stains, and fluid-phase markers in conjunction with electron, confocal, and conventional microscopy to characterize the vacuolar environments of these pathogens. The acidic nature of the C. burnetii-containing vacuole was confirmed by its acquisition of the acidotropic base acridine orange (AO). The presence of the vacuolar-type (H+) ATPase (V-ATPase) within the Coxiella vacuolar membrane was demonstrated by indirect immunofluorescence, and growth of C. burnetii was inhibited by bafilomycin A1 (Baf A), a specific inhibitor of the V-ATPase. In contrast, AO did not accumulate in C. trachomatis inclusions nor was the V-ATPase found in the inclusion membrane. Moreover, chlamydial growth was not inhibited by Baf A or the lysosomotropic amines methylamine, ammonium chloride, and chloroquine. Vacuoles harboring C. burnetii incorporated the fluorescent fluid- phase markers, fluorescein isothiocyanate-dextran (FITC-dex) and Lucifer yellow (LY), indicating trafficking between that vacuole and the endocytic pathway. Neither FITC-dex nor LY was sequestered by chlamydial inclusions. The late endosomal-prelysosomal marker cation-independent mannose 6-phosphate receptor was not detectable in the vacuolar membranes encompassing either parasite. However, the lysosomal enzymes acid phosphatase and cathepsin D and the lysosomal glycoproteins LAMP-1 and LAMP-2 localized to the C. burnetii vacuole but not the chlamydial vacuole. Interaction of C. trachomatis inclusions with the Golgi-derived vesicles was demonstrated by the transport of sphingomyelin, endogenously synthesized from C6-NBD-ceramide, to the chlamydial inclusion and incorporation into the bacterial cell wall. Similar trafficking of C-NBD-ceramide was not evident in C. burnetii-infected cells. Collectively, the data indicate that C. trachomatis replicates within a nonacidified vacuole that is disconnected from endosome-lysosome trafficking but may receive lipid from exocytic vesicles derived from the trans-Golgi network. These observations are in sharp contrast to those for C. burnetii, which by all criteria resides in a typical phagolysosome. |
DOI | 10.1128/IAI.64.3.796-809.1996 |
Alternate Journal | Infect Immun |
PubMed ID | 8641784 |
PubMed Central ID | PMC173840 |
Grant List | N01-HD-2-3144 / HD / NICHD NIH HHS / United States |