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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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M133 Tregs, but not bulk Tregs proliferate and are recruited to the brains of rJ2.2-infected mice.(A) Blood was obtained from B6-Foxp3gfp and M133 Tg-Foxp3gfp mice and analyzed for presence of M133-specific Tregs and Tconv using I-Ab/M133 tetramers. Representative plots after gating on CD4 T cells are shown. (B) Experimental design. Bulk and M133 Tregs were purified by flow cytometry from the spleen and LNs of Foxp3gfp and M133 Tg-Foxp3gfp mice, respectively, mixed at a 1∶1 ratio and labeled with Violet. A total of 3×105 cells were transferred to CD45/Thy1 congenic mice one day prior to infection with rJ2.2. (C) Gating strategy for identification of M133 and bulk Tregs in recipient mice is shown. (D) Representative plots showing proliferation of cells in the indicated tissues at day 7 p.i. The box in each panel indicates cells that have proliferated. N.D., not detectable. Percentages of divided cells are shown. (E) The ratio of M133 Treg/bulk Treg is shown. The data are representative of three independent experiments (A, C, D) or pooled from three experiments (E). (F) 2×105 M133 or Bulk Tregs were transferred to Thy1.1 mismatched mice and expression levels of indicated markers on transferred cells in the DCLN at day 4 p.i. are shown. To analyze bulk Tregs, cells from 5 recipient mice were pooled. Data are representative of analyses of three individual recipients (M133 Tregs) and 2 pooled samples (bulk Tregs).
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ppat-1004279-g001: M133 Tregs, but not bulk Tregs proliferate and are recruited to the brains of rJ2.2-infected mice.(A) Blood was obtained from B6-Foxp3gfp and M133 Tg-Foxp3gfp mice and analyzed for presence of M133-specific Tregs and Tconv using I-Ab/M133 tetramers. Representative plots after gating on CD4 T cells are shown. (B) Experimental design. Bulk and M133 Tregs were purified by flow cytometry from the spleen and LNs of Foxp3gfp and M133 Tg-Foxp3gfp mice, respectively, mixed at a 1∶1 ratio and labeled with Violet. A total of 3×105 cells were transferred to CD45/Thy1 congenic mice one day prior to infection with rJ2.2. (C) Gating strategy for identification of M133 and bulk Tregs in recipient mice is shown. (D) Representative plots showing proliferation of cells in the indicated tissues at day 7 p.i. The box in each panel indicates cells that have proliferated. N.D., not detectable. Percentages of divided cells are shown. (E) The ratio of M133 Treg/bulk Treg is shown. The data are representative of three independent experiments (A, C, D) or pooled from three experiments (E). (F) 2×105 M133 or Bulk Tregs were transferred to Thy1.1 mismatched mice and expression levels of indicated markers on transferred cells in the DCLN at day 4 p.i. are shown. To analyze bulk Tregs, cells from 5 recipient mice were pooled. Data are representative of analyses of three individual recipients (M133 Tregs) and 2 pooled samples (bulk Tregs).

Mentions: In the natural infection, M133-specific Tregs were detected in the rJ2.2-infected brain [12]. However, adoptively transferred bulk populations of splenic C57BL/6 (B6) Tregs (bulk Tregs) were minimally detected in the infected central nervous system (CNS) [7]. To reconcile these disparate results, we co-transferred bulk Tregs and M133 Tregs derived from uninfected Foxp3gfp and M133 Tg-Foxp3gfp mice, respectively. Approximately 0.5–1% of the CD4 T cells in the blood of M133 Tg mice expressed Foxp3; 50% of Foxp3+ and >97% of Foxp3−CD4 T cells (Tconv) bound I-Ab/M133 tetramer (Figure 1A). Equal numbers of Violet-labeled bulk and M133 Tregs were transferred to B6 mice, some of which were infected with rJ2.2 24 hours later (Figure 1B). Tregs were identified in the lymphoid tissues of infected and uninfected recipient mice seven days after infection, using the gating strategy shown in Figure 1C. Equal numbers of bulk and M133 Tregs were detected in the spleen, cervical and deep cervical lymph nodes (CLN, DCLN) of uninfected mice and neither population proliferated substantially. In contrast, after infection, M133 but not bulk Tregs proliferated extensively in all three peripheral lymphoid tissues. Further, only M133 Tregs entered the infected brain to a detectable extent (Figure 1D). By day 7 post infection (p.i.), the ratio of M133 to bulk Tregs ranged from 10∶1 in lymphoid tissue to greater than 1000∶1 in the brain (Figure 1E). In addition to exhibiting less proliferation, transferred bulk Tregs in the DCLN were less activated when assessed by measuring expression of CD25, CTLA-4, CXCR3 and ICOS at day 4 p.i. (Figure 1F).


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)

M133 Tregs, but not bulk Tregs proliferate and are recruited to the brains of rJ2.2-infected mice.(A) Blood was obtained from B6-Foxp3gfp and M133 Tg-Foxp3gfp mice and analyzed for presence of M133-specific Tregs and Tconv using I-Ab/M133 tetramers. Representative plots after gating on CD4 T cells are shown. (B) Experimental design. Bulk and M133 Tregs were purified by flow cytometry from the spleen and LNs of Foxp3gfp and M133 Tg-Foxp3gfp mice, respectively, mixed at a 1∶1 ratio and labeled with Violet. A total of 3×105 cells were transferred to CD45/Thy1 congenic mice one day prior to infection with rJ2.2. (C) Gating strategy for identification of M133 and bulk Tregs in recipient mice is shown. (D) Representative plots showing proliferation of cells in the indicated tissues at day 7 p.i. The box in each panel indicates cells that have proliferated. N.D., not detectable. Percentages of divided cells are shown. (E) The ratio of M133 Treg/bulk Treg is shown. The data are representative of three independent experiments (A, C, D) or pooled from three experiments (E). (F) 2×105 M133 or Bulk Tregs were transferred to Thy1.1 mismatched mice and expression levels of indicated markers on transferred cells in the DCLN at day 4 p.i. are shown. To analyze bulk Tregs, cells from 5 recipient mice were pooled. Data are representative of analyses of three individual recipients (M133 Tregs) and 2 pooled samples (bulk Tregs).
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Related In: Results  -  Collection

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ppat-1004279-g001: M133 Tregs, but not bulk Tregs proliferate and are recruited to the brains of rJ2.2-infected mice.(A) Blood was obtained from B6-Foxp3gfp and M133 Tg-Foxp3gfp mice and analyzed for presence of M133-specific Tregs and Tconv using I-Ab/M133 tetramers. Representative plots after gating on CD4 T cells are shown. (B) Experimental design. Bulk and M133 Tregs were purified by flow cytometry from the spleen and LNs of Foxp3gfp and M133 Tg-Foxp3gfp mice, respectively, mixed at a 1∶1 ratio and labeled with Violet. A total of 3×105 cells were transferred to CD45/Thy1 congenic mice one day prior to infection with rJ2.2. (C) Gating strategy for identification of M133 and bulk Tregs in recipient mice is shown. (D) Representative plots showing proliferation of cells in the indicated tissues at day 7 p.i. The box in each panel indicates cells that have proliferated. N.D., not detectable. Percentages of divided cells are shown. (E) The ratio of M133 Treg/bulk Treg is shown. The data are representative of three independent experiments (A, C, D) or pooled from three experiments (E). (F) 2×105 M133 or Bulk Tregs were transferred to Thy1.1 mismatched mice and expression levels of indicated markers on transferred cells in the DCLN at day 4 p.i. are shown. To analyze bulk Tregs, cells from 5 recipient mice were pooled. Data are representative of analyses of three individual recipients (M133 Tregs) and 2 pooled samples (bulk Tregs).
Mentions: In the natural infection, M133-specific Tregs were detected in the rJ2.2-infected brain [12]. However, adoptively transferred bulk populations of splenic C57BL/6 (B6) Tregs (bulk Tregs) were minimally detected in the infected central nervous system (CNS) [7]. To reconcile these disparate results, we co-transferred bulk Tregs and M133 Tregs derived from uninfected Foxp3gfp and M133 Tg-Foxp3gfp mice, respectively. Approximately 0.5–1% of the CD4 T cells in the blood of M133 Tg mice expressed Foxp3; 50% of Foxp3+ and >97% of Foxp3−CD4 T cells (Tconv) bound I-Ab/M133 tetramer (Figure 1A). Equal numbers of Violet-labeled bulk and M133 Tregs were transferred to B6 mice, some of which were infected with rJ2.2 24 hours later (Figure 1B). Tregs were identified in the lymphoid tissues of infected and uninfected recipient mice seven days after infection, using the gating strategy shown in Figure 1C. Equal numbers of bulk and M133 Tregs were detected in the spleen, cervical and deep cervical lymph nodes (CLN, DCLN) of uninfected mice and neither population proliferated substantially. In contrast, after infection, M133 but not bulk Tregs proliferated extensively in all three peripheral lymphoid tissues. Further, only M133 Tregs entered the infected brain to a detectable extent (Figure 1D). By day 7 post infection (p.i.), the ratio of M133 to bulk Tregs ranged from 10∶1 in lymphoid tissue to greater than 1000∶1 in the brain (Figure 1E). In addition to exhibiting less proliferation, transferred bulk Tregs in the DCLN were less activated when assessed by measuring expression of CD25, CTLA-4, CXCR3 and ICOS at day 4 p.i. (Figure 1F).

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