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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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T cells contacted dendritic cells in the meninges.A-C. A T cell that made contact with a dendritic cell for 5.4 min. During 25 min of imaging, the T cell indicated by the arrow contacted a dendritic cell (green, part of an agglomeration) at 18.3 min (A) remained in place (B), and left at 23.7 min (C). 25 dpi. D,E. A T cell (arrow, red) that remained in contact with a dendritic cell (yellow) throughout 20 min of imaging (S13 Video). 25 dpi. Both scale bars 20 μm. F-I. Illustrative plots of T cell speed changing with time. J. The mean skewness of the distribution of speed about the mean speed of at least 10 tracks per mouse was calculated and plotted against the number of T cells in the dura. Each symbol corresponds to one mouse. Purple symbols indicate three mice treated with abatacept.
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pntd.0003714.g008: T cells contacted dendritic cells in the meninges.A-C. A T cell that made contact with a dendritic cell for 5.4 min. During 25 min of imaging, the T cell indicated by the arrow contacted a dendritic cell (green, part of an agglomeration) at 18.3 min (A) remained in place (B), and left at 23.7 min (C). 25 dpi. D,E. A T cell (arrow, red) that remained in contact with a dendritic cell (yellow) throughout 20 min of imaging (S13 Video). 25 dpi. Both scale bars 20 μm. F-I. Illustrative plots of T cell speed changing with time. J. The mean skewness of the distribution of speed about the mean speed of at least 10 tracks per mouse was calculated and plotted against the number of T cells in the dura. Each symbol corresponds to one mouse. Purple symbols indicate three mice treated with abatacept.

Mentions: Long-lasting antigen presentation by dendritic cells to T cells, which is inhibited by abatacept, can profoundly modify the phenotype of a developing immune response [53, 54]. In infected hCD2(DsRed) x CD11c(EYFP) mice, visual inspection of videos showed that nearly all contacts lasted less than 2 min, but some longer contacts were observed, as in Fig 8A–8C (6 min) and Fig 8D and 8E (> 20 min, arrows; S13 Video). At least 17 cases of contact lasting more than 15 min were observed (in a total of 155 min of video record). T cells normally respond only to antigens presented on host MHC and in accordance with this rule they were not observed to make contact lasting more than a fraction of a second with trypanosomes (S9 Video).


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)

T cells contacted dendritic cells in the meninges.A-C. A T cell that made contact with a dendritic cell for 5.4 min. During 25 min of imaging, the T cell indicated by the arrow contacted a dendritic cell (green, part of an agglomeration) at 18.3 min (A) remained in place (B), and left at 23.7 min (C). 25 dpi. D,E. A T cell (arrow, red) that remained in contact with a dendritic cell (yellow) throughout 20 min of imaging (S13 Video). 25 dpi. Both scale bars 20 μm. F-I. Illustrative plots of T cell speed changing with time. J. The mean skewness of the distribution of speed about the mean speed of at least 10 tracks per mouse was calculated and plotted against the number of T cells in the dura. Each symbol corresponds to one mouse. Purple symbols indicate three mice treated with abatacept.
© Copyright Policy
Related In: Results  -  Collection

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

pntd.0003714.g008: T cells contacted dendritic cells in the meninges.A-C. A T cell that made contact with a dendritic cell for 5.4 min. During 25 min of imaging, the T cell indicated by the arrow contacted a dendritic cell (green, part of an agglomeration) at 18.3 min (A) remained in place (B), and left at 23.7 min (C). 25 dpi. D,E. A T cell (arrow, red) that remained in contact with a dendritic cell (yellow) throughout 20 min of imaging (S13 Video). 25 dpi. Both scale bars 20 μm. F-I. Illustrative plots of T cell speed changing with time. J. The mean skewness of the distribution of speed about the mean speed of at least 10 tracks per mouse was calculated and plotted against the number of T cells in the dura. Each symbol corresponds to one mouse. Purple symbols indicate three mice treated with abatacept.
Mentions: Long-lasting antigen presentation by dendritic cells to T cells, which is inhibited by abatacept, can profoundly modify the phenotype of a developing immune response [53, 54]. In infected hCD2(DsRed) x CD11c(EYFP) mice, visual inspection of videos showed that nearly all contacts lasted less than 2 min, but some longer contacts were observed, as in Fig 8A–8C (6 min) and Fig 8D and 8E (> 20 min, arrows; S13 Video). At least 17 cases of contact lasting more than 15 min were observed (in a total of 155 min of video record). T cells normally respond only to antigens presented on host MHC and in accordance with this rule they were not observed to make contact lasting more than a fraction of a second with trypanosomes (S9 Video).

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