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Idd9.2 and Idd9.3 protective alleles function in CD4+ T-cells and nonlymphoid cells to prevent expansion of pathogenic islet-specific CD8+ T-cells.

Hamilton-Williams EE, Wong SB, Martinez X, Rainbow DB, Hunter KM, Wicker LS, Sherman LA - Diabetes (2010)

Bottom Line: Interestingly, the Idd9.1 region, which provides significant protection from disease, did not prevent the expansion of autoreactive CD8(+) T-cells.Idd9 protective alleles are associated with reduced expansion of IGRP-specific CD8(+) T-cells.Protective alleles in the Idd9.2 congenic subregion are required for the maximal reduction of islet-specific CD8(+) T-cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, USA.

ABSTRACT

Objective: Multiple type 1 diabetes susceptibility genes have now been identified in both humans and mice, yet mechanistic understanding of how they impact disease pathogenesis is still minimal. We have sought to dissect the cellular basis for how the highly protective mouse Idd9 region limits the expansion of autoreactive CD8(+) T-cells, a key cell type in destruction of the islets.

Research design and methods: We assess the endogenous CD8(+) T-cell repertoire for reactivity to the islet antigen glucose-6-phosphatase-related protein (IGRP). Through the use of adoptively transferred T-cells, bone marrow chimeras, and reconstituted severe combined immunodeficient mice, we identify the protective cell types involved.

Results: IGRP-specific CD8(+) T-cells are present at low frequency in the insulitic lesions of Idd9 mice and could not be recalled in the periphery by viral expansion. We show that Idd9 genes act extrinsically to the CD8(+) T-cell to prevent the massive expansion of pathogenic effectors near the time of disease onset that occurs in NOD mice. The subregions Idd9.2 and Idd9.3 mediated this effect. Interestingly, the Idd9.1 region, which provides significant protection from disease, did not prevent the expansion of autoreactive CD8(+) T-cells. Expression of Idd9 genes was required by both CD4(+) T-cells and a nonlymphoid cell to induce optimal tolerance.

Conclusions: Idd9 protective alleles are associated with reduced expansion of IGRP-specific CD8(+) T-cells. Intrinsic expression of protective Idd9 alleles in CD4(+) T-cells and nonlymphoid cells is required to achieve an optimal level of tolerance. Protective alleles in the Idd9.2 congenic subregion are required for the maximal reduction of islet-specific CD8(+) T-cells.

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Expression of Idd9 genes by both hematopoietic cells and nonlymphocytes contributes to CD8+ T-cell tolerance. Recipient female Thy1.2+ mice were irradiated with 1200 rad and reconstituted with 7 × 106 T-cell–depleted bone marrow cells from Thy1.1+ donors (A) or a 50:50 mix of NOD and Idd9 bone marrow (B). After 12 weeks, the mice were infected with 1 × 107 pfu Vac-IGRP. Splenocytes were stained 7 days later with anti-CD8-FITC and IGRP-tetramer-PE. Pooled data from three experiments are shown. Horizontal line depicts median value. A: NOD→NOD vs. Idd9→NOD P = 0.0006 (***), NOD→NOD vs. NOD→Idd9 P = 0.006 (**), Idd9→NOD vs. Idd9→Idd9 P = 0.24, NOD→Idd9 vs. Idd9→Idd9 P = 0.004 (**), NOD→NOD vs. Idd9→Idd9 P < 0.0001 (Mann-Whitney test). B: NOD→NOD vs. mix→NOD P = 0.005 (**), NOD→NOD vs. Idd9→Idd9 P = 0.016 (Mann-Whitney test). C: NOD-SCID and Idd9-SCID mice were reconstituted with 2 × 107 spleen and LN cells from 3- to 4-week-old NOD or Idd9 mice. After 10 weeks, the mice were infected with Vac-IGRP, and IGRP-tetramer+ CD8+ T-cells were measured in the spleen 7 days later. Pooled data from three experiments are shown.
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Figure 6: Expression of Idd9 genes by both hematopoietic cells and nonlymphocytes contributes to CD8+ T-cell tolerance. Recipient female Thy1.2+ mice were irradiated with 1200 rad and reconstituted with 7 × 106 T-cell–depleted bone marrow cells from Thy1.1+ donors (A) or a 50:50 mix of NOD and Idd9 bone marrow (B). After 12 weeks, the mice were infected with 1 × 107 pfu Vac-IGRP. Splenocytes were stained 7 days later with anti-CD8-FITC and IGRP-tetramer-PE. Pooled data from three experiments are shown. Horizontal line depicts median value. A: NOD→NOD vs. Idd9→NOD P = 0.0006 (***), NOD→NOD vs. NOD→Idd9 P = 0.006 (**), Idd9→NOD vs. Idd9→Idd9 P = 0.24, NOD→Idd9 vs. Idd9→Idd9 P = 0.004 (**), NOD→NOD vs. Idd9→Idd9 P < 0.0001 (Mann-Whitney test). B: NOD→NOD vs. mix→NOD P = 0.005 (**), NOD→NOD vs. Idd9→Idd9 P = 0.016 (Mann-Whitney test). C: NOD-SCID and Idd9-SCID mice were reconstituted with 2 × 107 spleen and LN cells from 3- to 4-week-old NOD or Idd9 mice. After 10 weeks, the mice were infected with Vac-IGRP, and IGRP-tetramer+ CD8+ T-cells were measured in the spleen 7 days later. Pooled data from three experiments are shown.

Mentions: Radiation chimeras were produced to determine which host cell types must express Idd9 genes for maintenance of tolerance. Thy1.2+ Idd9 or NOD recipients were irradiated and reconstituted with Thy1.1+ Idd9 or NOD bone marrow cells and rested for 12 weeks. Reconstitution with Thy1.1+ donor T-cells varied between 71 and 88%, with no difference observed in reconstitution by NOD versus Idd9 bone marrow (supplementary Fig. 4). After infection with Vac-IGRP, the frequency of tetramer+ cells in the NOD→NOD chimeras was significantly higher than that found in the Idd9→Idd9 chimeras (2.9 vs. 0.5%, Fig. 6A). When Idd9 bone marrow was used to reconstitute NOD hosts, IGRP-specific tolerance was well maintained compared with NOD→NOD (0.5%, Fig. 6A). Thus, an Idd9 hematopoietic cell is able to restore CD8+ T-cell tolerance in an NOD host. NOD→Idd9 chimeric mice (0.9%) had significantly fewer IGRP-specific cells than NOD→NOD, yet significantly more than Idd9→Idd9 (Fig. 6A). This may be due to tolerance by expression of Idd9 genes within a host parenchymal cell, or the 20% residual Idd9 hematopoietic cells may have a sufficiently strong dominant effect to afford some tolerance, or both.


Idd9.2 and Idd9.3 protective alleles function in CD4+ T-cells and nonlymphoid cells to prevent expansion of pathogenic islet-specific CD8+ T-cells.

Hamilton-Williams EE, Wong SB, Martinez X, Rainbow DB, Hunter KM, Wicker LS, Sherman LA - Diabetes (2010)

Expression of Idd9 genes by both hematopoietic cells and nonlymphocytes contributes to CD8+ T-cell tolerance. Recipient female Thy1.2+ mice were irradiated with 1200 rad and reconstituted with 7 × 106 T-cell–depleted bone marrow cells from Thy1.1+ donors (A) or a 50:50 mix of NOD and Idd9 bone marrow (B). After 12 weeks, the mice were infected with 1 × 107 pfu Vac-IGRP. Splenocytes were stained 7 days later with anti-CD8-FITC and IGRP-tetramer-PE. Pooled data from three experiments are shown. Horizontal line depicts median value. A: NOD→NOD vs. Idd9→NOD P = 0.0006 (***), NOD→NOD vs. NOD→Idd9 P = 0.006 (**), Idd9→NOD vs. Idd9→Idd9 P = 0.24, NOD→Idd9 vs. Idd9→Idd9 P = 0.004 (**), NOD→NOD vs. Idd9→Idd9 P < 0.0001 (Mann-Whitney test). B: NOD→NOD vs. mix→NOD P = 0.005 (**), NOD→NOD vs. Idd9→Idd9 P = 0.016 (Mann-Whitney test). C: NOD-SCID and Idd9-SCID mice were reconstituted with 2 × 107 spleen and LN cells from 3- to 4-week-old NOD or Idd9 mice. After 10 weeks, the mice were infected with Vac-IGRP, and IGRP-tetramer+ CD8+ T-cells were measured in the spleen 7 days later. Pooled data from three experiments are shown.
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Figure 6: Expression of Idd9 genes by both hematopoietic cells and nonlymphocytes contributes to CD8+ T-cell tolerance. Recipient female Thy1.2+ mice were irradiated with 1200 rad and reconstituted with 7 × 106 T-cell–depleted bone marrow cells from Thy1.1+ donors (A) or a 50:50 mix of NOD and Idd9 bone marrow (B). After 12 weeks, the mice were infected with 1 × 107 pfu Vac-IGRP. Splenocytes were stained 7 days later with anti-CD8-FITC and IGRP-tetramer-PE. Pooled data from three experiments are shown. Horizontal line depicts median value. A: NOD→NOD vs. Idd9→NOD P = 0.0006 (***), NOD→NOD vs. NOD→Idd9 P = 0.006 (**), Idd9→NOD vs. Idd9→Idd9 P = 0.24, NOD→Idd9 vs. Idd9→Idd9 P = 0.004 (**), NOD→NOD vs. Idd9→Idd9 P < 0.0001 (Mann-Whitney test). B: NOD→NOD vs. mix→NOD P = 0.005 (**), NOD→NOD vs. Idd9→Idd9 P = 0.016 (Mann-Whitney test). C: NOD-SCID and Idd9-SCID mice were reconstituted with 2 × 107 spleen and LN cells from 3- to 4-week-old NOD or Idd9 mice. After 10 weeks, the mice were infected with Vac-IGRP, and IGRP-tetramer+ CD8+ T-cells were measured in the spleen 7 days later. Pooled data from three experiments are shown.
Mentions: Radiation chimeras were produced to determine which host cell types must express Idd9 genes for maintenance of tolerance. Thy1.2+ Idd9 or NOD recipients were irradiated and reconstituted with Thy1.1+ Idd9 or NOD bone marrow cells and rested for 12 weeks. Reconstitution with Thy1.1+ donor T-cells varied between 71 and 88%, with no difference observed in reconstitution by NOD versus Idd9 bone marrow (supplementary Fig. 4). After infection with Vac-IGRP, the frequency of tetramer+ cells in the NOD→NOD chimeras was significantly higher than that found in the Idd9→Idd9 chimeras (2.9 vs. 0.5%, Fig. 6A). When Idd9 bone marrow was used to reconstitute NOD hosts, IGRP-specific tolerance was well maintained compared with NOD→NOD (0.5%, Fig. 6A). Thus, an Idd9 hematopoietic cell is able to restore CD8+ T-cell tolerance in an NOD host. NOD→Idd9 chimeric mice (0.9%) had significantly fewer IGRP-specific cells than NOD→NOD, yet significantly more than Idd9→Idd9 (Fig. 6A). This may be due to tolerance by expression of Idd9 genes within a host parenchymal cell, or the 20% residual Idd9 hematopoietic cells may have a sufficiently strong dominant effect to afford some tolerance, or both.

Bottom Line: Interestingly, the Idd9.1 region, which provides significant protection from disease, did not prevent the expansion of autoreactive CD8(+) T-cells.Idd9 protective alleles are associated with reduced expansion of IGRP-specific CD8(+) T-cells.Protective alleles in the Idd9.2 congenic subregion are required for the maximal reduction of islet-specific CD8(+) T-cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, USA.

ABSTRACT

Objective: Multiple type 1 diabetes susceptibility genes have now been identified in both humans and mice, yet mechanistic understanding of how they impact disease pathogenesis is still minimal. We have sought to dissect the cellular basis for how the highly protective mouse Idd9 region limits the expansion of autoreactive CD8(+) T-cells, a key cell type in destruction of the islets.

Research design and methods: We assess the endogenous CD8(+) T-cell repertoire for reactivity to the islet antigen glucose-6-phosphatase-related protein (IGRP). Through the use of adoptively transferred T-cells, bone marrow chimeras, and reconstituted severe combined immunodeficient mice, we identify the protective cell types involved.

Results: IGRP-specific CD8(+) T-cells are present at low frequency in the insulitic lesions of Idd9 mice and could not be recalled in the periphery by viral expansion. We show that Idd9 genes act extrinsically to the CD8(+) T-cell to prevent the massive expansion of pathogenic effectors near the time of disease onset that occurs in NOD mice. The subregions Idd9.2 and Idd9.3 mediated this effect. Interestingly, the Idd9.1 region, which provides significant protection from disease, did not prevent the expansion of autoreactive CD8(+) T-cells. Expression of Idd9 genes was required by both CD4(+) T-cells and a nonlymphoid cell to induce optimal tolerance.

Conclusions: Idd9 protective alleles are associated with reduced expansion of IGRP-specific CD8(+) T-cells. Intrinsic expression of protective Idd9 alleles in CD4(+) T-cells and nonlymphoid cells is required to achieve an optimal level of tolerance. Protective alleles in the Idd9.2 congenic subregion are required for the maximal reduction of islet-specific CD8(+) T-cells.

Show MeSH
Related in: MedlinePlus