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Dermal-type macrophages expressing CD209/DC-SIGN show inherent resistance to dengue virus growth.

Kwan WH, Navarro-Sanchez E, Dumortier H, Decossas M, Vachon H, dos Santos FB, Fridman HW, Rey FA, Harris E, Despres P, Mueller CG - PLoS Negl Trop Dis (2008)

Bottom Line: Here, we showed that dermal macrophages bound recombinant envelope E glycoprotein fused to green fluorescent protein.The macrophages were able to internalize the virus, but progeny virus production was undetectable in the infected cells.In addition, no IFN-alpha was produced in response to the virus.

View Article: PubMed Central - PubMed

Affiliation: CNRS, Laboratory of Therapeutic Immunology and Chemistry, IBMC, Université Louis Pasteur, Strasbourg, France.

ABSTRACT

Background: An important question in dengue pathogenesis is the identity of immune cells involved in the control of dengue virus infection at the site of the mosquito bite. There is evidence that infection of immature myeloid dendritic cells plays a crucial role in dengue pathogenesis and that the interaction of the viral envelope E glycoprotein with CD209/DC-SIGN is a key element for their productive infection. Dermal macrophages express CD209, yet little is known about their role in dengue virus infection.

Methods and findings: Here, we showed that dermal macrophages bound recombinant envelope E glycoprotein fused to green fluorescent protein. Because dermal macrophages stain for IL-10 in situ, we generated dermal-type macrophages from monocytes in the presence of IL-10 to study their infection by dengue virus. The macrophages were able to internalize the virus, but progeny virus production was undetectable in the infected cells. In addition, no IFN-alpha was produced in response to the virus. The inability of dengue virus to grow in the macrophages was attributable to accumulation of internalized virus particles into poorly-acidified phagosomes.

Conclusions: Aborting infection by viral sequestration in early phagosomes would present a novel means to curb infection of enveloped virus and may constitute a prime defense system to prevent dengue virus spread shortly after the bite of the infected mosquito.

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Related in: MedlinePlus

DV3 sE-eGFP protein-containing vesicles are distinct in MDDC and MDdMφ.Cells were processed for electron-microscopic localization of sE-eGFP using gold-conjugated anti-GFP Ab followed by silver enhancement. Five min after incubation with sE-eGFP, the protein was bound to the plasma membrane (arrow heads) and entered both cell-types in small endosomes, invaginated from the plasma membrane (arrows). At 30 min, in MDDC, sE-eGFP was localized to small, peri-nuclear endosomes, often associated with the ER, whereas in MDdMφ, the sE-eGFP was concentrated in large phagosomes. The inset shows a high-magnification view of sE-eGFP inside a tubular-shaped vesicle.
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pntd-0000311-g005: DV3 sE-eGFP protein-containing vesicles are distinct in MDDC and MDdMφ.Cells were processed for electron-microscopic localization of sE-eGFP using gold-conjugated anti-GFP Ab followed by silver enhancement. Five min after incubation with sE-eGFP, the protein was bound to the plasma membrane (arrow heads) and entered both cell-types in small endosomes, invaginated from the plasma membrane (arrows). At 30 min, in MDDC, sE-eGFP was localized to small, peri-nuclear endosomes, often associated with the ER, whereas in MDdMφ, the sE-eGFP was concentrated in large phagosomes. The inset shows a high-magnification view of sE-eGFP inside a tubular-shaped vesicle.

Mentions: In an effort to define the molecular basis of the inability of DV to grow in MDdMφ. we asked whether internalized DV was sequestered in a manner that hampers productive infection, using DV3 sE-eGFP fusion protein. To monitor DV3 sE protein internalization in MDdMφ and MDDC, the cells were incubated with pH-sensitive LysoSensor dye and analyzed by confocal microscopy (Fig. 4). This dye accumulates in acidic organelles, where its fluorescence emission is highest. After 5 min at 37°C, DV3 sE protein was observed in vesicle-like structures in both cell-types. By 30 min and 60 min, DV3 sE protein dispersed to acidified perinuclear lysosomes in MDDC. In marked contrast, when MDdMφ were examined at these time-points, a large fraction of internalized DV3 sE protein was excluded from the acidic compartment and remained in non-acidic, large endosomes. Electron microscopy analysis using a colloidal gold-conjugated antibody to GFP demonstrated that DV3 sE protein accumulated in large phagosomes in MDdMφ, located close to the plasma membrane (Fig. 5). On the other hand, at 30 min, in MDDC, DV3 sE protein was mostly found in small perinuclear vesicles in the environment of the endoplasmic reticulum. Taken together, these data suggest that the inability of DV to productively infect MDdMφ is due to accumulation of virus particles in immature endosomal vesicles whose pH does not allow efficient viral-cell membrane fusion and subsequent virus uncoating.


Dermal-type macrophages expressing CD209/DC-SIGN show inherent resistance to dengue virus growth.

Kwan WH, Navarro-Sanchez E, Dumortier H, Decossas M, Vachon H, dos Santos FB, Fridman HW, Rey FA, Harris E, Despres P, Mueller CG - PLoS Negl Trop Dis (2008)

DV3 sE-eGFP protein-containing vesicles are distinct in MDDC and MDdMφ.Cells were processed for electron-microscopic localization of sE-eGFP using gold-conjugated anti-GFP Ab followed by silver enhancement. Five min after incubation with sE-eGFP, the protein was bound to the plasma membrane (arrow heads) and entered both cell-types in small endosomes, invaginated from the plasma membrane (arrows). At 30 min, in MDDC, sE-eGFP was localized to small, peri-nuclear endosomes, often associated with the ER, whereas in MDdMφ, the sE-eGFP was concentrated in large phagosomes. The inset shows a high-magnification view of sE-eGFP inside a tubular-shaped vesicle.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2553280&req=5

pntd-0000311-g005: DV3 sE-eGFP protein-containing vesicles are distinct in MDDC and MDdMφ.Cells were processed for electron-microscopic localization of sE-eGFP using gold-conjugated anti-GFP Ab followed by silver enhancement. Five min after incubation with sE-eGFP, the protein was bound to the plasma membrane (arrow heads) and entered both cell-types in small endosomes, invaginated from the plasma membrane (arrows). At 30 min, in MDDC, sE-eGFP was localized to small, peri-nuclear endosomes, often associated with the ER, whereas in MDdMφ, the sE-eGFP was concentrated in large phagosomes. The inset shows a high-magnification view of sE-eGFP inside a tubular-shaped vesicle.
Mentions: In an effort to define the molecular basis of the inability of DV to grow in MDdMφ. we asked whether internalized DV was sequestered in a manner that hampers productive infection, using DV3 sE-eGFP fusion protein. To monitor DV3 sE protein internalization in MDdMφ and MDDC, the cells were incubated with pH-sensitive LysoSensor dye and analyzed by confocal microscopy (Fig. 4). This dye accumulates in acidic organelles, where its fluorescence emission is highest. After 5 min at 37°C, DV3 sE protein was observed in vesicle-like structures in both cell-types. By 30 min and 60 min, DV3 sE protein dispersed to acidified perinuclear lysosomes in MDDC. In marked contrast, when MDdMφ were examined at these time-points, a large fraction of internalized DV3 sE protein was excluded from the acidic compartment and remained in non-acidic, large endosomes. Electron microscopy analysis using a colloidal gold-conjugated antibody to GFP demonstrated that DV3 sE protein accumulated in large phagosomes in MDdMφ, located close to the plasma membrane (Fig. 5). On the other hand, at 30 min, in MDDC, DV3 sE protein was mostly found in small perinuclear vesicles in the environment of the endoplasmic reticulum. Taken together, these data suggest that the inability of DV to productively infect MDdMφ is due to accumulation of virus particles in immature endosomal vesicles whose pH does not allow efficient viral-cell membrane fusion and subsequent virus uncoating.

Bottom Line: Here, we showed that dermal macrophages bound recombinant envelope E glycoprotein fused to green fluorescent protein.The macrophages were able to internalize the virus, but progeny virus production was undetectable in the infected cells.In addition, no IFN-alpha was produced in response to the virus.

View Article: PubMed Central - PubMed

Affiliation: CNRS, Laboratory of Therapeutic Immunology and Chemistry, IBMC, Université Louis Pasteur, Strasbourg, France.

ABSTRACT

Background: An important question in dengue pathogenesis is the identity of immune cells involved in the control of dengue virus infection at the site of the mosquito bite. There is evidence that infection of immature myeloid dendritic cells plays a crucial role in dengue pathogenesis and that the interaction of the viral envelope E glycoprotein with CD209/DC-SIGN is a key element for their productive infection. Dermal macrophages express CD209, yet little is known about their role in dengue virus infection.

Methods and findings: Here, we showed that dermal macrophages bound recombinant envelope E glycoprotein fused to green fluorescent protein. Because dermal macrophages stain for IL-10 in situ, we generated dermal-type macrophages from monocytes in the presence of IL-10 to study their infection by dengue virus. The macrophages were able to internalize the virus, but progeny virus production was undetectable in the infected cells. In addition, no IFN-alpha was produced in response to the virus. The inability of dengue virus to grow in the macrophages was attributable to accumulation of internalized virus particles into poorly-acidified phagosomes.

Conclusions: Aborting infection by viral sequestration in early phagosomes would present a novel means to curb infection of enveloped virus and may constitute a prime defense system to prevent dengue virus spread shortly after the bite of the infected mosquito.

Show MeSH
Related in: MedlinePlus