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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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Abatacept reduced the increase in meningeal T cells.A. CD2+ (DsRed) cells in the meninges at 11 dpi, untreated control. Z-projection, 15 μm. Blue from SHG indicates the proximity of the skull. B. A companion mouse treated with abatacept. C. Numbers of meningeal T cells and dendritic cells, in uninfected controls, and untreated and treated mice at 11–12 dpi. Each symbol is the mean for several fields for one mouse. p values were calculated by Student's t test after log transformation. D. Mean speeds of T cells in three untreated and three treated mice. E. Parasitemia (blue) and numbers of meningeal trypanosomes (green) in infected mice at 11–12 dpi without or with abatacept treatment. Each symbol corresponds to one mouse.
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pntd.0003714.g007: Abatacept reduced the increase in meningeal T cells.A. CD2+ (DsRed) cells in the meninges at 11 dpi, untreated control. Z-projection, 15 μm. Blue from SHG indicates the proximity of the skull. B. A companion mouse treated with abatacept. C. Numbers of meningeal T cells and dendritic cells, in uninfected controls, and untreated and treated mice at 11–12 dpi. Each symbol is the mean for several fields for one mouse. p values were calculated by Student's t test after log transformation. D. Mean speeds of T cells in three untreated and three treated mice. E. Parasitemia (blue) and numbers of meningeal trypanosomes (green) in infected mice at 11–12 dpi without or with abatacept treatment. Each symbol corresponds to one mouse.

Mentions: To examine the role of antigen presentation to T cells in trypanosomal meningitis, we treated mice with abatacept (CTLA4Ig, Orencia), which inhibits activation of naive T cells, in part by binding to CD80/86 on antigen-presenting cells, such as dendritic cells, and inhibiting their interaction with the co-stimulatory receptor CD28 on T cells [52]. To image both T cells and dendritic cells, we created hCD2(DsRed)xCD11c(EYFP) mice. These were injected intraperitoneally with abatacept (10 mg/kg) on alternate days from -1 dpi, and the meninges imaged at 11 or 12 dpi. This treatment markedly reduced the numbers of meningeal T cells and dendritic cells at 11–12 dpi, by factors of about ten (Fig 7A, 7B and 7C). The remaining T cells had a significantly reduced displacement rate (Fig 7D) in part as a consequence of a reduction in mean speed from 11.64 ± 0.34 μm/min (mean ± SEM, n = 3 mice) to 5.2 ± 1.2 μm/min (n = 3; p = 0.007). However, treatment with abatacept had no evident effect on parasitemia (Fig 7E). Nor was there a conclusive effect on the numbers of trypansomes in the dura: trypanosomes were detected in the meninges of 2 of 6 untreated mice, and in one of 6 treated mice (Fig 7E), Thus abatacept greatly reduced and modified the immune response in the dura, but its effect, if any, on the early appearance of trypanosomes there is unresolved.


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)

Abatacept reduced the increase in meningeal T cells.A. CD2+ (DsRed) cells in the meninges at 11 dpi, untreated control. Z-projection, 15 μm. Blue from SHG indicates the proximity of the skull. B. A companion mouse treated with abatacept. C. Numbers of meningeal T cells and dendritic cells, in uninfected controls, and untreated and treated mice at 11–12 dpi. Each symbol is the mean for several fields for one mouse. p values were calculated by Student's t test after log transformation. D. Mean speeds of T cells in three untreated and three treated mice. E. Parasitemia (blue) and numbers of meningeal trypanosomes (green) in infected mice at 11–12 dpi without or with abatacept treatment. Each symbol corresponds to one mouse.
© Copyright Policy
Related In: Results  -  Collection

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

pntd.0003714.g007: Abatacept reduced the increase in meningeal T cells.A. CD2+ (DsRed) cells in the meninges at 11 dpi, untreated control. Z-projection, 15 μm. Blue from SHG indicates the proximity of the skull. B. A companion mouse treated with abatacept. C. Numbers of meningeal T cells and dendritic cells, in uninfected controls, and untreated and treated mice at 11–12 dpi. Each symbol is the mean for several fields for one mouse. p values were calculated by Student's t test after log transformation. D. Mean speeds of T cells in three untreated and three treated mice. E. Parasitemia (blue) and numbers of meningeal trypanosomes (green) in infected mice at 11–12 dpi without or with abatacept treatment. Each symbol corresponds to one mouse.
Mentions: To examine the role of antigen presentation to T cells in trypanosomal meningitis, we treated mice with abatacept (CTLA4Ig, Orencia), which inhibits activation of naive T cells, in part by binding to CD80/86 on antigen-presenting cells, such as dendritic cells, and inhibiting their interaction with the co-stimulatory receptor CD28 on T cells [52]. To image both T cells and dendritic cells, we created hCD2(DsRed)xCD11c(EYFP) mice. These were injected intraperitoneally with abatacept (10 mg/kg) on alternate days from -1 dpi, and the meninges imaged at 11 or 12 dpi. This treatment markedly reduced the numbers of meningeal T cells and dendritic cells at 11–12 dpi, by factors of about ten (Fig 7A, 7B and 7C). The remaining T cells had a significantly reduced displacement rate (Fig 7D) in part as a consequence of a reduction in mean speed from 11.64 ± 0.34 μm/min (mean ± SEM, n = 3 mice) to 5.2 ± 1.2 μm/min (n = 3; p = 0.007). However, treatment with abatacept had no evident effect on parasitemia (Fig 7E). Nor was there a conclusive effect on the numbers of trypansomes in the dura: trypanosomes were detected in the meninges of 2 of 6 untreated mice, and in one of 6 treated mice (Fig 7E), Thus abatacept greatly reduced and modified the immune response in the dura, but its effect, if any, on the early appearance of trypanosomes there is unresolved.

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