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Intravital imaging of a massive lymphocyte response in the cortical dura of mice after peripheral infection by trypanosomes.

Coles JA, Myburgh E, Ritchie R, Hamilton A, Rodgers J, Mottram JC, Barrett MP, Brewer JM - PLoS Negl Trop Dis (2015)

Bottom Line: Making use of optical signals from the skull bone, blood vessels and dural cells, we conclude that up to 40 dpi, the extravascular trypanosomes were essentially confined to the dura, as were the great majority of the T cells.Inhibition of T cell activation by intraperitoneal injection of abatacept reduced the numbers of meningeal T cells at 12 dpi and their mean speed fell from 11.64 ± 0.34 μm/min (mean ± SEM) to 5.2 ± 1.2 μm/min (p = 0.007).The population and motility of the trypanosomes tended to decline after about 30 dpi.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom; Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.

ABSTRACT
Peripheral infection by Trypanosoma brucei, the protozoan responsible for sleeping sickness, activates lymphocytes, and, at later stages, causes meningoencephalitis. We have videoed the cortical meninges and superficial parenchyma of C56BL/6 reporter mice infected with T.b.brucei. By use of a two-photon microscope to image through the thinned skull, the integrity of the tissues was maintained. We observed a 47-fold increase in CD2+ T cells in the meninges by 12 days post infection (dpi). CD11c+ dendritic cells also increased, and extravascular trypanosomes, made visible either by expression of a fluorescent protein, or by intravenous injection of furamidine, appeared. The likelihood that invasion will spread from the meninges to the parenchyma will depend strongly on whether the trypanosomes are below the arachnoid membrane, or above it, in the dura. Making use of optical signals from the skull bone, blood vessels and dural cells, we conclude that up to 40 dpi, the extravascular trypanosomes were essentially confined to the dura, as were the great majority of the T cells. Inhibition of T cell activation by intraperitoneal injection of abatacept reduced the numbers of meningeal T cells at 12 dpi and their mean speed fell from 11.64 ± 0.34 μm/min (mean ± SEM) to 5.2 ± 1.2 μm/min (p = 0.007). The T cells occasionally made contact lasting tens of minutes with dendritic cells, indicative of antigen presentation. The population and motility of the trypanosomes tended to decline after about 30 dpi. We suggest that the lymphocyte infiltration of the meninges may later contribute to encephalitis, but have no evidence that the dural trypanosomes invade the parenchyma.

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Infection increases the number of dendritic cells in the meninges.A. In uninfected mice, there was a small population of CD11c+ (EYFP) cells (yellow) in the meninges, mainly close to dural vessels (gray). B. The numbers increased by 12 dpi. SHG signal (blue) indicates the proximity of the skull; blood vessels are magenta. C. Approximate numbers of dendritic cells per unit area of meninges. Each symbol is the mean for one mouse. D. In a 3D reconstruction of a 139 μm Z-stack at 27 dpi, the dendritic cells are seen to be close under the skull (blue) and above or beside vessels (magenta). The grid spacing is 42.4 μm E. At 11 dpi in the same mouse as (B) a deeper XY plane shows only two CD11c+(YFP) cells, located on horizontal pial vessels embedded in the brain surface (arrows). Arrowheads point to vertical vessels below the pia mater.
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pntd.0003714.g002: Infection increases the number of dendritic cells in the meninges.A. In uninfected mice, there was a small population of CD11c+ (EYFP) cells (yellow) in the meninges, mainly close to dural vessels (gray). B. The numbers increased by 12 dpi. SHG signal (blue) indicates the proximity of the skull; blood vessels are magenta. C. Approximate numbers of dendritic cells per unit area of meninges. Each symbol is the mean for one mouse. D. In a 3D reconstruction of a 139 μm Z-stack at 27 dpi, the dendritic cells are seen to be close under the skull (blue) and above or beside vessels (magenta). The grid spacing is 42.4 μm E. At 11 dpi in the same mouse as (B) a deeper XY plane shows only two CD11c+(YFP) cells, located on horizontal pial vessels embedded in the brain surface (arrows). Arrowheads point to vertical vessels below the pia mater.

Mentions: T cells are dependent on signals from antigen-presenting cells, notably dendritic cells, for activation, and dendritic cells are present in the normal murine dura [28, 41]. We imaged reporter mice expressing Enhanced Yellow Fluorescent Protein (EYFP) under control of the CD11c promoter so that myeloid dendritic cells and a small sub-population of macrophages were fluorescent [36]. In uninfected mice, small numbers of CD11c+(EYFP) cells were present, located on meningeal vessels (Fig 2A). Most had the irregular shape and constant extension and retraction of processes that identified them as dendritic cells (Fig 2A and S1 Video). A few CD11c+ cells were spherical and usually not adjacent to blood vessels (not shown).


Intravital imaging of a massive lymphocyte response in the cortical dura of mice after peripheral infection by trypanosomes.

Coles JA, Myburgh E, Ritchie R, Hamilton A, Rodgers J, Mottram JC, Barrett MP, Brewer JM - PLoS Negl Trop Dis (2015)

Infection increases the number of dendritic cells in the meninges.A. In uninfected mice, there was a small population of CD11c+ (EYFP) cells (yellow) in the meninges, mainly close to dural vessels (gray). B. The numbers increased by 12 dpi. SHG signal (blue) indicates the proximity of the skull; blood vessels are magenta. C. Approximate numbers of dendritic cells per unit area of meninges. Each symbol is the mean for one mouse. D. In a 3D reconstruction of a 139 μm Z-stack at 27 dpi, the dendritic cells are seen to be close under the skull (blue) and above or beside vessels (magenta). The grid spacing is 42.4 μm E. At 11 dpi in the same mouse as (B) a deeper XY plane shows only two CD11c+(YFP) cells, located on horizontal pial vessels embedded in the brain surface (arrows). Arrowheads point to vertical vessels below the pia mater.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4400075&req=5

pntd.0003714.g002: Infection increases the number of dendritic cells in the meninges.A. In uninfected mice, there was a small population of CD11c+ (EYFP) cells (yellow) in the meninges, mainly close to dural vessels (gray). B. The numbers increased by 12 dpi. SHG signal (blue) indicates the proximity of the skull; blood vessels are magenta. C. Approximate numbers of dendritic cells per unit area of meninges. Each symbol is the mean for one mouse. D. In a 3D reconstruction of a 139 μm Z-stack at 27 dpi, the dendritic cells are seen to be close under the skull (blue) and above or beside vessels (magenta). The grid spacing is 42.4 μm E. At 11 dpi in the same mouse as (B) a deeper XY plane shows only two CD11c+(YFP) cells, located on horizontal pial vessels embedded in the brain surface (arrows). Arrowheads point to vertical vessels below the pia mater.
Mentions: T cells are dependent on signals from antigen-presenting cells, notably dendritic cells, for activation, and dendritic cells are present in the normal murine dura [28, 41]. We imaged reporter mice expressing Enhanced Yellow Fluorescent Protein (EYFP) under control of the CD11c promoter so that myeloid dendritic cells and a small sub-population of macrophages were fluorescent [36]. In uninfected mice, small numbers of CD11c+(EYFP) cells were present, located on meningeal vessels (Fig 2A). Most had the irregular shape and constant extension and retraction of processes that identified them as dendritic cells (Fig 2A and S1 Video). A few CD11c+ cells were spherical and usually not adjacent to blood vessels (not shown).

Bottom Line: Making use of optical signals from the skull bone, blood vessels and dural cells, we conclude that up to 40 dpi, the extravascular trypanosomes were essentially confined to the dura, as were the great majority of the T cells.Inhibition of T cell activation by intraperitoneal injection of abatacept reduced the numbers of meningeal T cells at 12 dpi and their mean speed fell from 11.64 ± 0.34 μm/min (mean ± SEM) to 5.2 ± 1.2 μm/min (p = 0.007).The population and motility of the trypanosomes tended to decline after about 30 dpi.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom; Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom.

ABSTRACT
Peripheral infection by Trypanosoma brucei, the protozoan responsible for sleeping sickness, activates lymphocytes, and, at later stages, causes meningoencephalitis. We have videoed the cortical meninges and superficial parenchyma of C56BL/6 reporter mice infected with T.b.brucei. By use of a two-photon microscope to image through the thinned skull, the integrity of the tissues was maintained. We observed a 47-fold increase in CD2+ T cells in the meninges by 12 days post infection (dpi). CD11c+ dendritic cells also increased, and extravascular trypanosomes, made visible either by expression of a fluorescent protein, or by intravenous injection of furamidine, appeared. The likelihood that invasion will spread from the meninges to the parenchyma will depend strongly on whether the trypanosomes are below the arachnoid membrane, or above it, in the dura. Making use of optical signals from the skull bone, blood vessels and dural cells, we conclude that up to 40 dpi, the extravascular trypanosomes were essentially confined to the dura, as were the great majority of the T cells. Inhibition of T cell activation by intraperitoneal injection of abatacept reduced the numbers of meningeal T cells at 12 dpi and their mean speed fell from 11.64 ± 0.34 μm/min (mean ± SEM) to 5.2 ± 1.2 μm/min (p = 0.007). The T cells occasionally made contact lasting tens of minutes with dendritic cells, indicative of antigen presentation. The population and motility of the trypanosomes tended to decline after about 30 dpi. We suggest that the lymphocyte infiltration of the meninges may later contribute to encephalitis, but have no evidence that the dural trypanosomes invade the parenchyma.

Show MeSH
Related in: MedlinePlus