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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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The location of meningeal T cells.A. T cells (red) were present at the level of extracellular collagen (blue). One T cell (arrow) can be seen in S8 Video squeezing through collagen. 11 dpi. B. T Cells (red) and dendritic cells (yellow) were both mainly above the larger horizontal vessels (magenta). 12 dpi. The imaged area is 424 μm square. C. A single plane from the Z-stack of (B). The plane is slightly oblique and includes skull or collagen (blue, upper left) and vertical parenchymal vessels (right, arrow, blood marker shown in green). T cells (red) and dendritic cells (yellow) were at the level of dural vessels. D. A Z-stack acquired over 741s showing blurred trypanosomes (green) among T cells (red). 11 dpi. The grid spacing is 42.4 μm. E. At 30 dpi, T cells are seen adjacent to large horizontal veins. F. At 39 dpi, occasional T cells are seen at more than 50 μm below the pia mater (arrow). All scale bars are 50 μm.
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pntd.0003714.g005: The location of meningeal T cells.A. T cells (red) were present at the level of extracellular collagen (blue). One T cell (arrow) can be seen in S8 Video squeezing through collagen. 11 dpi. B. T Cells (red) and dendritic cells (yellow) were both mainly above the larger horizontal vessels (magenta). 12 dpi. The imaged area is 424 μm square. C. A single plane from the Z-stack of (B). The plane is slightly oblique and includes skull or collagen (blue, upper left) and vertical parenchymal vessels (right, arrow, blood marker shown in green). T cells (red) and dendritic cells (yellow) were at the level of dural vessels. D. A Z-stack acquired over 741s showing blurred trypanosomes (green) among T cells (red). 11 dpi. The grid spacing is 42.4 μm. E. At 30 dpi, T cells are seen adjacent to large horizontal veins. F. At 39 dpi, occasional T cells are seen at more than 50 μm below the pia mater (arrow). All scale bars are 50 μm.

Mentions: Like trypanosomes, T cells were seen close under the skull at the level of extracellular collagen (Fig 5A and S8 Video). At 12 dpi, they were mainly above the horizontal pial vessels, as seen in a 3D reconstruction (Fig 5B) and a slightly oblique single plane (Fig 5C). Dendritic cells were at the same level (Fig 5B and 5C). T cells (at 11 dpi) were seen to be present at the same level as trypanosomes (Fig 5D and S9 Video). However, at 30 dpi, T cells were seen adjacent to large pial veins (Fig 5E) and at 39 dpi, occasional T cells were seen some 50 μm below the pia mater (Fig 5F). In summary, the increase in T cells is greatest in the dura, but T cells can be present at deeper levels.


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)

The location of meningeal T cells.A. T cells (red) were present at the level of extracellular collagen (blue). One T cell (arrow) can be seen in S8 Video squeezing through collagen. 11 dpi. B. T Cells (red) and dendritic cells (yellow) were both mainly above the larger horizontal vessels (magenta). 12 dpi. The imaged area is 424 μm square. C. A single plane from the Z-stack of (B). The plane is slightly oblique and includes skull or collagen (blue, upper left) and vertical parenchymal vessels (right, arrow, blood marker shown in green). T cells (red) and dendritic cells (yellow) were at the level of dural vessels. D. A Z-stack acquired over 741s showing blurred trypanosomes (green) among T cells (red). 11 dpi. The grid spacing is 42.4 μm. E. At 30 dpi, T cells are seen adjacent to large horizontal veins. F. At 39 dpi, occasional T cells are seen at more than 50 μm below the pia mater (arrow). All scale bars are 50 μm.
© Copyright Policy
Related In: Results  -  Collection

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

pntd.0003714.g005: The location of meningeal T cells.A. T cells (red) were present at the level of extracellular collagen (blue). One T cell (arrow) can be seen in S8 Video squeezing through collagen. 11 dpi. B. T Cells (red) and dendritic cells (yellow) were both mainly above the larger horizontal vessels (magenta). 12 dpi. The imaged area is 424 μm square. C. A single plane from the Z-stack of (B). The plane is slightly oblique and includes skull or collagen (blue, upper left) and vertical parenchymal vessels (right, arrow, blood marker shown in green). T cells (red) and dendritic cells (yellow) were at the level of dural vessels. D. A Z-stack acquired over 741s showing blurred trypanosomes (green) among T cells (red). 11 dpi. The grid spacing is 42.4 μm. E. At 30 dpi, T cells are seen adjacent to large horizontal veins. F. At 39 dpi, occasional T cells are seen at more than 50 μm below the pia mater (arrow). All scale bars are 50 μm.
Mentions: Like trypanosomes, T cells were seen close under the skull at the level of extracellular collagen (Fig 5A and S8 Video). At 12 dpi, they were mainly above the horizontal pial vessels, as seen in a 3D reconstruction (Fig 5B) and a slightly oblique single plane (Fig 5C). Dendritic cells were at the same level (Fig 5B and 5C). T cells (at 11 dpi) were seen to be present at the same level as trypanosomes (Fig 5D and S9 Video). However, at 30 dpi, T cells were seen adjacent to large pial veins (Fig 5E) and at 39 dpi, occasional T cells were seen some 50 μm below the pia mater (Fig 5F). In summary, the increase in T cells is greatest in the dura, but T cells can be present at deeper levels.

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