Limits...
CD4+CD25+ T regulatory cells dependent on ICOS promote regulation of effector cells in the prediabetic lesion.

Herman AE, Freeman GJ, Mathis D, Benoist C - J. Exp. Med. (2004)

Bottom Line: Here, we report that Tregs and T effector cells (Teffs) coexist within the pancreatic lesion before type 1 diabetes onset.We find that BDC2.5 T cell receptor transgenic animals contain a small subset of FoxP3 positive CD4+CD25+CD69- cells in the pancreas, actively turning over, expressing the clonotypic receptor, and containing functional regulatory activity.Blockade of ICOS rapidly converts early insulitis to diabetes, which disrupts the balance of Teffs and Tregs and promotes a very broad shift in the expression of the T regulatory-specific profile.

View Article: PubMed Central - PubMed

Affiliation: Section on Immunology and Immunogenetics, Joslin Diabetes Center, Boston, MA 02215, USA.

ABSTRACT
CD4+CD25+ T regulatory cells (Tregs) prevent autoimmune disease, yet little is known about precisely where they exert their influence naturally in a spontaneous autoimmune disorder. Here, we report that Tregs and T effector cells (Teffs) coexist within the pancreatic lesion before type 1 diabetes onset. We find that BDC2.5 T cell receptor transgenic animals contain a small subset of FoxP3 positive CD4+CD25+CD69- cells in the pancreas, actively turning over, expressing the clonotypic receptor, and containing functional regulatory activity. Gene expression profiling confirms that the CD4+CD25+CD69- cells in pancreatic tissue express transcripts diagnostic of regulatory cells, but with significantly higher levels of interleukin 10 and inducible costimulator (ICOS) than their lymph node counterparts. Blockade of ICOS rapidly converts early insulitis to diabetes, which disrupts the balance of Teffs and Tregs and promotes a very broad shift in the expression of the T regulatory-specific profile. Thus, CD4+CD25+69- Tregs operate directly in the autoimmune lesion and are dependent on ICOS to keep it in a nondestructive state.

Show MeSH

Related in: MedlinePlus

IL-10, GITR, and ICOS are specifically up-regulated in the pancreatic lesion compared with the draining lymph node. (A) Cells were sorted to high purity from the pancreas lesion, pancreatic LNs (PLN), or mesenteric LNs (MLN) of 3–4-wk-old BDC2.5 mice for the CD4+CD25+CD69−, CD25loCD69+, or CD25−CD69− populations. mRNA was prepared from each indicated group and assessed for IL-10 expression by real-time PCR analysis. Data are presented as relative expression of IL-10 compared with the value in whole LNs (set to 1). The average of three experiments is shown. (B) GITR expression (unshaded histograms) was examined on CD4+B220− live lymphocytes gated on the CD25/CD69 profiles indicated (Fig. 1 B) from the pancreas, PLN, or MLN and compared with isotype control (shaded histograms). The data shown are representative of three experiments. (C) ICOS expression (unshaded histograms) was examined on subsets as in B. The data shown are representative of five experiments.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2211778&req=5

fig5: IL-10, GITR, and ICOS are specifically up-regulated in the pancreatic lesion compared with the draining lymph node. (A) Cells were sorted to high purity from the pancreas lesion, pancreatic LNs (PLN), or mesenteric LNs (MLN) of 3–4-wk-old BDC2.5 mice for the CD4+CD25+CD69−, CD25loCD69+, or CD25−CD69− populations. mRNA was prepared from each indicated group and assessed for IL-10 expression by real-time PCR analysis. Data are presented as relative expression of IL-10 compared with the value in whole LNs (set to 1). The average of three experiments is shown. (B) GITR expression (unshaded histograms) was examined on CD4+B220− live lymphocytes gated on the CD25/CD69 profiles indicated (Fig. 1 B) from the pancreas, PLN, or MLN and compared with isotype control (shaded histograms). The data shown are representative of three experiments. (C) ICOS expression (unshaded histograms) was examined on subsets as in B. The data shown are representative of five experiments.

Mentions: To compare more directly the differences between Tregs found in tissue and their LN counterparts, we examined the expression of several regulatory molecules by flow cytometry or real-time PCR. IL-10 is an important effector molecule for Tregs in several in vivo systems (for review see references 14–16) and has been shown to be critical for regulation in the BDC2.5 model (47). We observed that IL-10 was highly up-regulated in Treg in the pancreatic lesion compared with effector cells (Table SI). We compared mRNA levels of IL-10 in Tregs isolated from the pancreatic infiltrate or LN. Unlike FoxP3 levels, which were similar between LNs and pancreatic Tregs (Fig. 1), IL-10 levels were 15–36-fold higher in pancreatic Tregs compared with those isolated from the PLN or irrelevant mesenteric LN (MLN; Fig. 5 A). The GITR molecule was also consistently present at somewhat higher levels on pancreatic versus LN Tregs (Fig. 5 B), as well as increasing on activated cells in the pancreas. ICOS, a CD28 family member, is known to be an important costimulatory receptor for the production of IL-10 (48–51). Although ICOS is usually thought to act as a positive costimulator, genetic deficiency or Ab blockade of ICOS leads to exacerbation of disease in mouse models of multiple sclerosis (48, 51). ICOS was expressed on a small subpopulation (5–10%) of CD25+CD69− Tregs in the LN, although interestingly ICOS was always lower or absent on PLN Tregs (Fig. 5 C). Strikingly, 30–80% of CD25+CD69− Tregs in the pancreas expressed ICOS. Recently activated cells (CD25lo CD69+) showed no comparable ICOS expression. In some experiments, ICOS was present on CD25loCD69+ cells in the pancreas (2–16%), but was of lower intensity. CD25− CD69− cells did not express ICOS (unpublished data). These data suggest that Tregs in the autoimmune lesion acquire functional and phenotypic properties distinct from their LN counterparts, in particular marked by high expression of ICOS. Higher levels of the regulatory cytokine IL-10, GITR, and ICOS in Tregs specifically from the pancreatic lesion suggest that Tregs function directly in the target organ to mediate regulation.


CD4+CD25+ T regulatory cells dependent on ICOS promote regulation of effector cells in the prediabetic lesion.

Herman AE, Freeman GJ, Mathis D, Benoist C - J. Exp. Med. (2004)

IL-10, GITR, and ICOS are specifically up-regulated in the pancreatic lesion compared with the draining lymph node. (A) Cells were sorted to high purity from the pancreas lesion, pancreatic LNs (PLN), or mesenteric LNs (MLN) of 3–4-wk-old BDC2.5 mice for the CD4+CD25+CD69−, CD25loCD69+, or CD25−CD69− populations. mRNA was prepared from each indicated group and assessed for IL-10 expression by real-time PCR analysis. Data are presented as relative expression of IL-10 compared with the value in whole LNs (set to 1). The average of three experiments is shown. (B) GITR expression (unshaded histograms) was examined on CD4+B220− live lymphocytes gated on the CD25/CD69 profiles indicated (Fig. 1 B) from the pancreas, PLN, or MLN and compared with isotype control (shaded histograms). The data shown are representative of three experiments. (C) ICOS expression (unshaded histograms) was examined on subsets as in B. The data shown are representative of five experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2211778&req=5

fig5: IL-10, GITR, and ICOS are specifically up-regulated in the pancreatic lesion compared with the draining lymph node. (A) Cells were sorted to high purity from the pancreas lesion, pancreatic LNs (PLN), or mesenteric LNs (MLN) of 3–4-wk-old BDC2.5 mice for the CD4+CD25+CD69−, CD25loCD69+, or CD25−CD69− populations. mRNA was prepared from each indicated group and assessed for IL-10 expression by real-time PCR analysis. Data are presented as relative expression of IL-10 compared with the value in whole LNs (set to 1). The average of three experiments is shown. (B) GITR expression (unshaded histograms) was examined on CD4+B220− live lymphocytes gated on the CD25/CD69 profiles indicated (Fig. 1 B) from the pancreas, PLN, or MLN and compared with isotype control (shaded histograms). The data shown are representative of three experiments. (C) ICOS expression (unshaded histograms) was examined on subsets as in B. The data shown are representative of five experiments.
Mentions: To compare more directly the differences between Tregs found in tissue and their LN counterparts, we examined the expression of several regulatory molecules by flow cytometry or real-time PCR. IL-10 is an important effector molecule for Tregs in several in vivo systems (for review see references 14–16) and has been shown to be critical for regulation in the BDC2.5 model (47). We observed that IL-10 was highly up-regulated in Treg in the pancreatic lesion compared with effector cells (Table SI). We compared mRNA levels of IL-10 in Tregs isolated from the pancreatic infiltrate or LN. Unlike FoxP3 levels, which were similar between LNs and pancreatic Tregs (Fig. 1), IL-10 levels were 15–36-fold higher in pancreatic Tregs compared with those isolated from the PLN or irrelevant mesenteric LN (MLN; Fig. 5 A). The GITR molecule was also consistently present at somewhat higher levels on pancreatic versus LN Tregs (Fig. 5 B), as well as increasing on activated cells in the pancreas. ICOS, a CD28 family member, is known to be an important costimulatory receptor for the production of IL-10 (48–51). Although ICOS is usually thought to act as a positive costimulator, genetic deficiency or Ab blockade of ICOS leads to exacerbation of disease in mouse models of multiple sclerosis (48, 51). ICOS was expressed on a small subpopulation (5–10%) of CD25+CD69− Tregs in the LN, although interestingly ICOS was always lower or absent on PLN Tregs (Fig. 5 C). Strikingly, 30–80% of CD25+CD69− Tregs in the pancreas expressed ICOS. Recently activated cells (CD25lo CD69+) showed no comparable ICOS expression. In some experiments, ICOS was present on CD25loCD69+ cells in the pancreas (2–16%), but was of lower intensity. CD25− CD69− cells did not express ICOS (unpublished data). These data suggest that Tregs in the autoimmune lesion acquire functional and phenotypic properties distinct from their LN counterparts, in particular marked by high expression of ICOS. Higher levels of the regulatory cytokine IL-10, GITR, and ICOS in Tregs specifically from the pancreatic lesion suggest that Tregs function directly in the target organ to mediate regulation.

Bottom Line: Here, we report that Tregs and T effector cells (Teffs) coexist within the pancreatic lesion before type 1 diabetes onset.We find that BDC2.5 T cell receptor transgenic animals contain a small subset of FoxP3 positive CD4+CD25+CD69- cells in the pancreas, actively turning over, expressing the clonotypic receptor, and containing functional regulatory activity.Blockade of ICOS rapidly converts early insulitis to diabetes, which disrupts the balance of Teffs and Tregs and promotes a very broad shift in the expression of the T regulatory-specific profile.

View Article: PubMed Central - PubMed

Affiliation: Section on Immunology and Immunogenetics, Joslin Diabetes Center, Boston, MA 02215, USA.

ABSTRACT
CD4+CD25+ T regulatory cells (Tregs) prevent autoimmune disease, yet little is known about precisely where they exert their influence naturally in a spontaneous autoimmune disorder. Here, we report that Tregs and T effector cells (Teffs) coexist within the pancreatic lesion before type 1 diabetes onset. We find that BDC2.5 T cell receptor transgenic animals contain a small subset of FoxP3 positive CD4+CD25+CD69- cells in the pancreas, actively turning over, expressing the clonotypic receptor, and containing functional regulatory activity. Gene expression profiling confirms that the CD4+CD25+CD69- cells in pancreatic tissue express transcripts diagnostic of regulatory cells, but with significantly higher levels of interleukin 10 and inducible costimulator (ICOS) than their lymph node counterparts. Blockade of ICOS rapidly converts early insulitis to diabetes, which disrupts the balance of Teffs and Tregs and promotes a very broad shift in the expression of the T regulatory-specific profile. Thus, CD4+CD25+69- Tregs operate directly in the autoimmune lesion and are dependent on ICOS to keep it in a nondestructive state.

Show MeSH
Related in: MedlinePlus