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Virus-specific regulatory T cells ameliorate encephalitis by repressing effector T cell functions from priming to effector stages.

Zhao J, Zhao J, Perlman S - PLoS Pathog. (2014)

Bottom Line: In addition, M133 Tregs diminished microglia activation and decreased the number and function of Tconv in the infected brain.Thus, virus-specific Tregs inhibited pathogenic CD4 T cell responses during priming and effector stages, particularly those recognizing cognate antigen, and decreased mortality and morbidity without affecting virus clearance.These cells are more suppressive than bulk Tregs and provide a targeted approach to ameliorating immunopathological disease in infectious settings.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America.

ABSTRACT
Several studies have demonstrated the presence of pathogen-specific Foxp3+ CD4 regulatory T cells (Treg) in infected animals, but little is known about where and how these cells affect the effector T cell responses and whether they are more suppressive than bulk Treg populations. We recently showed the presence of both epitope M133-specific Tregs (M133 Treg) and conventional CD4 T cells (M133 Tconv) in the brains of mice with coronavirus-induced encephalitis. Here, we provide new insights into the interactions between pathogenic Tconv and Tregs responding to the same epitope. M133 Tregs inhibited the proliferation but not initial activation of M133 Tconv in draining lymph nodes (DLN). Further, M133 Tregs inhibited migration of M133 Tconv from the DLN. In addition, M133 Tregs diminished microglia activation and decreased the number and function of Tconv in the infected brain. Thus, virus-specific Tregs inhibited pathogenic CD4 T cell responses during priming and effector stages, particularly those recognizing cognate antigen, and decreased mortality and morbidity without affecting virus clearance. These cells are more suppressive than bulk Tregs and provide a targeted approach to ameliorating immunopathological disease in infectious settings.

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Related in: MedlinePlus

Transferred M133 Tregs enhance survival and diminish the M133 Tconv immune response in the brain.105 M133 Tregs, bulk Tregs or B6-derived Foxp3−CD4 T cells (control group) were transferred to Thy1 congenic mice one day prior to rJ2.2 infection. (A) M133 Treg numbers in spleen, DCLN and brain of recipient mice from days 0 to 41 p.i. (B–D) Survival (B), weight loss (C) and viral titers in the brains (D) of recipient mice were monitored. 18–22 mice in 4 independent experiments were analyzed for survival and weight loss. In (C), *P<0.05, **P<0.01 weights of M133 Treg recipients compared to mice that received bulk Tregs or control cells; (E–G) Lymphocytes were prepared from brains of recipient mice at day 7 p.i. and stimulated with the indicated peptides. (E) Frequencies of S510 and S598-specific cells within the CD8 T cell population and M133- and S358-specific cells within the CD4 T cell population are shown. 6–10 mice in 3–5 independent experiments were analyzed. (F) Brain-derived lymphocytes were harvested from mice that received control cells or M133 Tregs. Representative dot plots show IFN-γ and IL-10 expression by endogenous CD4 T cells after M133 peptide stimulation. Summary data show expression levels of IFN-γ by M133-specific CD4 T cells in the absence (black) or presence (red) of M133 Treg. (G) Representative dot plots (from the same sample as in F (right hand dot plot)) show IFN-γ and IL-10 expression by exogenous M133 Tregs. Note that lower levels of IFN-γ were expressed by M133 Tregs when compared to Tconv. Summary data show expression levels of IL-10 by IFN-γ- (black) and IFN-γ+ M133 Tregs (red). Data in (F) and (G) are representative of three independent experiments with at least 3 mice/group. (H) Expression levels of MHC II on brain microglia at day 7 p.i. Data are representative of three independent experiments with 3–5 mice/group. *P<0.05, **P<0.01, ***P<0.001.
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ppat-1004279-g008: Transferred M133 Tregs enhance survival and diminish the M133 Tconv immune response in the brain.105 M133 Tregs, bulk Tregs or B6-derived Foxp3−CD4 T cells (control group) were transferred to Thy1 congenic mice one day prior to rJ2.2 infection. (A) M133 Treg numbers in spleen, DCLN and brain of recipient mice from days 0 to 41 p.i. (B–D) Survival (B), weight loss (C) and viral titers in the brains (D) of recipient mice were monitored. 18–22 mice in 4 independent experiments were analyzed for survival and weight loss. In (C), *P<0.05, **P<0.01 weights of M133 Treg recipients compared to mice that received bulk Tregs or control cells; (E–G) Lymphocytes were prepared from brains of recipient mice at day 7 p.i. and stimulated with the indicated peptides. (E) Frequencies of S510 and S598-specific cells within the CD8 T cell population and M133- and S358-specific cells within the CD4 T cell population are shown. 6–10 mice in 3–5 independent experiments were analyzed. (F) Brain-derived lymphocytes were harvested from mice that received control cells or M133 Tregs. Representative dot plots show IFN-γ and IL-10 expression by endogenous CD4 T cells after M133 peptide stimulation. Summary data show expression levels of IFN-γ by M133-specific CD4 T cells in the absence (black) or presence (red) of M133 Treg. (G) Representative dot plots (from the same sample as in F (right hand dot plot)) show IFN-γ and IL-10 expression by exogenous M133 Tregs. Note that lower levels of IFN-γ were expressed by M133 Tregs when compared to Tconv. Summary data show expression levels of IL-10 by IFN-γ- (black) and IFN-γ+ M133 Tregs (red). Data in (F) and (G) are representative of three independent experiments with at least 3 mice/group. (H) Expression levels of MHC II on brain microglia at day 7 p.i. Data are representative of three independent experiments with 3–5 mice/group. *P<0.05, **P<0.01, ***P<0.001.

Mentions: To examine the effects of transferred M133 Tregs on clinical disease, we transferred 105 M133 Tregs (in the absence of M133 Tconv), bulk Tregs or bulk Tconv (control group) to infected mice one day prior to rJ2.2 infection. Consistent with priming in the DCLN, numbers of M133 Tregs increased dramatically from day 0 to day 3 p.i. in the DCLN but not the spleen. M133 Tregs were first detected in the brain at day 3, peaked at day 7 in both the brain and DCLN and then gradually declined in both organs as the infection resolved (Figure 8A). Transferred M133 Tregs, but not bulk Tregs improved survival and diminished weight loss (Figure 8, B and C) without affecting virus clearance (Figure 8D). M133 Tregs decreased the frequencies of M133-specific CD4 T cells in the brain (Figure 8E). In addition, transferred M133 Tregs inhibited the effector function of these cells, manifested by reduced IFN-γ expression per cell (Figure 8F). The transferred Tregs also diminished the frequency of CD4 T cells recognizing the subdominant CD4 T cell epitope (epitope S358) but did not change the CD8 T cell response to the immunodominant S510 and subdominant S598 epitopes (Figure 8E).


Virus-specific regulatory T cells ameliorate encephalitis by repressing effector T cell functions from priming to effector stages.

Zhao J, Zhao J, Perlman S - PLoS Pathog. (2014)

Transferred M133 Tregs enhance survival and diminish the M133 Tconv immune response in the brain.105 M133 Tregs, bulk Tregs or B6-derived Foxp3−CD4 T cells (control group) were transferred to Thy1 congenic mice one day prior to rJ2.2 infection. (A) M133 Treg numbers in spleen, DCLN and brain of recipient mice from days 0 to 41 p.i. (B–D) Survival (B), weight loss (C) and viral titers in the brains (D) of recipient mice were monitored. 18–22 mice in 4 independent experiments were analyzed for survival and weight loss. In (C), *P<0.05, **P<0.01 weights of M133 Treg recipients compared to mice that received bulk Tregs or control cells; (E–G) Lymphocytes were prepared from brains of recipient mice at day 7 p.i. and stimulated with the indicated peptides. (E) Frequencies of S510 and S598-specific cells within the CD8 T cell population and M133- and S358-specific cells within the CD4 T cell population are shown. 6–10 mice in 3–5 independent experiments were analyzed. (F) Brain-derived lymphocytes were harvested from mice that received control cells or M133 Tregs. Representative dot plots show IFN-γ and IL-10 expression by endogenous CD4 T cells after M133 peptide stimulation. Summary data show expression levels of IFN-γ by M133-specific CD4 T cells in the absence (black) or presence (red) of M133 Treg. (G) Representative dot plots (from the same sample as in F (right hand dot plot)) show IFN-γ and IL-10 expression by exogenous M133 Tregs. Note that lower levels of IFN-γ were expressed by M133 Tregs when compared to Tconv. Summary data show expression levels of IL-10 by IFN-γ- (black) and IFN-γ+ M133 Tregs (red). Data in (F) and (G) are representative of three independent experiments with at least 3 mice/group. (H) Expression levels of MHC II on brain microglia at day 7 p.i. Data are representative of three independent experiments with 3–5 mice/group. *P<0.05, **P<0.01, ***P<0.001.
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Related In: Results  -  Collection

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ppat-1004279-g008: Transferred M133 Tregs enhance survival and diminish the M133 Tconv immune response in the brain.105 M133 Tregs, bulk Tregs or B6-derived Foxp3−CD4 T cells (control group) were transferred to Thy1 congenic mice one day prior to rJ2.2 infection. (A) M133 Treg numbers in spleen, DCLN and brain of recipient mice from days 0 to 41 p.i. (B–D) Survival (B), weight loss (C) and viral titers in the brains (D) of recipient mice were monitored. 18–22 mice in 4 independent experiments were analyzed for survival and weight loss. In (C), *P<0.05, **P<0.01 weights of M133 Treg recipients compared to mice that received bulk Tregs or control cells; (E–G) Lymphocytes were prepared from brains of recipient mice at day 7 p.i. and stimulated with the indicated peptides. (E) Frequencies of S510 and S598-specific cells within the CD8 T cell population and M133- and S358-specific cells within the CD4 T cell population are shown. 6–10 mice in 3–5 independent experiments were analyzed. (F) Brain-derived lymphocytes were harvested from mice that received control cells or M133 Tregs. Representative dot plots show IFN-γ and IL-10 expression by endogenous CD4 T cells after M133 peptide stimulation. Summary data show expression levels of IFN-γ by M133-specific CD4 T cells in the absence (black) or presence (red) of M133 Treg. (G) Representative dot plots (from the same sample as in F (right hand dot plot)) show IFN-γ and IL-10 expression by exogenous M133 Tregs. Note that lower levels of IFN-γ were expressed by M133 Tregs when compared to Tconv. Summary data show expression levels of IL-10 by IFN-γ- (black) and IFN-γ+ M133 Tregs (red). Data in (F) and (G) are representative of three independent experiments with at least 3 mice/group. (H) Expression levels of MHC II on brain microglia at day 7 p.i. Data are representative of three independent experiments with 3–5 mice/group. *P<0.05, **P<0.01, ***P<0.001.
Mentions: To examine the effects of transferred M133 Tregs on clinical disease, we transferred 105 M133 Tregs (in the absence of M133 Tconv), bulk Tregs or bulk Tconv (control group) to infected mice one day prior to rJ2.2 infection. Consistent with priming in the DCLN, numbers of M133 Tregs increased dramatically from day 0 to day 3 p.i. in the DCLN but not the spleen. M133 Tregs were first detected in the brain at day 3, peaked at day 7 in both the brain and DCLN and then gradually declined in both organs as the infection resolved (Figure 8A). Transferred M133 Tregs, but not bulk Tregs improved survival and diminished weight loss (Figure 8, B and C) without affecting virus clearance (Figure 8D). M133 Tregs decreased the frequencies of M133-specific CD4 T cells in the brain (Figure 8E). In addition, transferred M133 Tregs inhibited the effector function of these cells, manifested by reduced IFN-γ expression per cell (Figure 8F). The transferred Tregs also diminished the frequency of CD4 T cells recognizing the subdominant CD4 T cell epitope (epitope S358) but did not change the CD8 T cell response to the immunodominant S510 and subdominant S598 epitopes (Figure 8E).

Bottom Line: In addition, M133 Tregs diminished microglia activation and decreased the number and function of Tconv in the infected brain.Thus, virus-specific Tregs inhibited pathogenic CD4 T cell responses during priming and effector stages, particularly those recognizing cognate antigen, and decreased mortality and morbidity without affecting virus clearance.These cells are more suppressive than bulk Tregs and provide a targeted approach to ameliorating immunopathological disease in infectious settings.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America.

ABSTRACT
Several studies have demonstrated the presence of pathogen-specific Foxp3+ CD4 regulatory T cells (Treg) in infected animals, but little is known about where and how these cells affect the effector T cell responses and whether they are more suppressive than bulk Treg populations. We recently showed the presence of both epitope M133-specific Tregs (M133 Treg) and conventional CD4 T cells (M133 Tconv) in the brains of mice with coronavirus-induced encephalitis. Here, we provide new insights into the interactions between pathogenic Tconv and Tregs responding to the same epitope. M133 Tregs inhibited the proliferation but not initial activation of M133 Tconv in draining lymph nodes (DLN). Further, M133 Tregs inhibited migration of M133 Tconv from the DLN. In addition, M133 Tregs diminished microglia activation and decreased the number and function of Tconv in the infected brain. Thus, virus-specific Tregs inhibited pathogenic CD4 T cell responses during priming and effector stages, particularly those recognizing cognate antigen, and decreased mortality and morbidity without affecting virus clearance. These cells are more suppressive than bulk Tregs and provide a targeted approach to ameliorating immunopathological disease in infectious settings.

Show MeSH
Related in: MedlinePlus