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Generation of human CD8 T regulatory cells by CD40 ligand-activated plasmacytoid dendritic cells.

Gilliet M, Liu YJ - J. Exp. Med. (2002)

Bottom Line: Unlike DC1-primed CD8 T cells that produced large amounts of interferon (IFN)-gamma upon restimulation, DC2-primed CD8 T cells produced significant amounts of interleukin (IL)-10, low IFN-gamma, and no IL-4, IL-5, nor transforming growth factor (TGF)-beta.This inhibition was mediated by IL-10, but not by TGF-beta.IL-10-producing CD8 T cells could not inhibit the proliferation of DC1-preactivated effector T cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, DNAX Research Institute of Molecular and Cellular Biology, 901 California Avenue, Palo Alto, CA 94304, USA.

ABSTRACT
Although CD8 T cell-mediated immunosuppression has been a well-known phenomenon during the last three decades, the nature of primary CD8 T suppressor cells and the mechanism underlying their generation remain enigmatic. We demonstrated that naive CD8 T cells primed with allogeneic CD40 ligand-activated plasmacytoid dendritic cells (DC)2 differentiated into CD8 T cells that displayed poor secondary proliferative and cytolytic responses. By contrast, naive CD8 T cells primed with allogeneic CD40 ligand-activated monocyte-derived DCs (DC1) differentiated into CD8 T cells, which proliferated to secondary stimulation and killed allogeneic target cells. Unlike DC1-primed CD8 T cells that produced large amounts of interferon (IFN)-gamma upon restimulation, DC2-primed CD8 T cells produced significant amounts of interleukin (IL)-10, low IFN-gamma, and no IL-4, IL-5, nor transforming growth factor (TGF)-beta. The addition of anti-IL-10-neutralizing monoclonal antibodies during DC2 and CD8 T cell coculture, completely blocked the generation of IL-10-producing anergic CD8 T cells. IL-10-producing CD8 T cells strongly inhibit the allospecific proliferation of naive CD8 T cells to monocytes, and mature and immature DCs. This inhibition was mediated by IL-10, but not by TGF-beta. IL-10-producing CD8 T cells could inhibit the bystander proliferation of naive CD8 T cells, provided that they were restimulated nearby to produce IL-10. IL-10-producing CD8 T cells could not inhibit the proliferation of DC1-preactivated effector T cells. This study demonstrates that IL-10-producing CD8 T cells are regulatory T cells, which provides a cellular basis for the phenomenon of CD8 T cell-mediated immunosuppression and suggests a role for plasmacytoid DC2 in immunological tolerance.

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DC2-primed CD8 T cells exhibit poor cytolytic activity and are hyporesponsive to secondary restimulation. (A) CD8 T cells were primed for 6 d with DC1 (•, ▪) and DC2 (○, □), and collected and tested for their ability to lyse allogeneic (•, ○) or autologous (▪, □) B cells. The results represent six independent experiments. (B) CD8 T cells primed with DC1 and DC2 for 6 d were collected and restimulated with DC1 and DC2 derived from the donor used for priming. CD8 T cell expansion (upper panels), proliferation (middle panels), and increase in cell size (lower panel) were determined after 3 d of restimulation. Histograms represent CD8 T cell size before (filled) and after restimulation (open histograms). The results represent three independent experiments. (C) CD8 T cells from donor A were primed for 6 d with DC1 and DC2 from donor B, and then restimulated with DC1 from donor B or donor C. Proliferation was determined after 3 d of restimulation. (D) IFN-γ and IL-10 in the supernatants of CD8 T cells, restimulated as described in C for 2 d.
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fig2: DC2-primed CD8 T cells exhibit poor cytolytic activity and are hyporesponsive to secondary restimulation. (A) CD8 T cells were primed for 6 d with DC1 (•, ▪) and DC2 (○, □), and collected and tested for their ability to lyse allogeneic (•, ○) or autologous (▪, □) B cells. The results represent six independent experiments. (B) CD8 T cells primed with DC1 and DC2 for 6 d were collected and restimulated with DC1 and DC2 derived from the donor used for priming. CD8 T cell expansion (upper panels), proliferation (middle panels), and increase in cell size (lower panel) were determined after 3 d of restimulation. Histograms represent CD8 T cell size before (filled) and after restimulation (open histograms). The results represent three independent experiments. (C) CD8 T cells from donor A were primed for 6 d with DC1 and DC2 from donor B, and then restimulated with DC1 from donor B or donor C. Proliferation was determined after 3 d of restimulation. (D) IFN-γ and IL-10 in the supernatants of CD8 T cells, restimulated as described in C for 2 d.

Mentions: Whereas CD8 T cells primed by DC1 were potent cytotoxic effectors lysing allogeneic targets at low E/T ratios, CD8 T cells primed with DC2 displayed poor alloantigen-specific cytotoxicity (Fig. 2 A), but expressed similar levels of perforin and granzyme B (unpublished data). In addition, CD8 T cells primed with DC1 responded strongly to secondary restimulation with allogeneic DC1 or DC2, whereas CD8 T cells primed with DC2 were hyporesponsive to secondary restimulation with DC1 or DC2, as determined by proliferation and blastogenesis (Fig. 2 B). However, DC2-primed CD8 T cells were able to mount a proliferative response to third-party alloantigens (Fig. 2 C). This is because in contrast to previously described IL-10–producing Tr1 cell clones that display the same allo-specificity (7), DC2-primed CD8 T cells derived from a 6-d primary cell culture not only contain antigen-specific anergic CD8 T cells, but also unprimed naive T cells with other specificities. Therefore, upon restimulation with the original alloantigen, DC2-primed anergic CD8 T cells will not proliferate, whereas unprimed CD8 T cells specific to the third-party alloantigen will undergo primary proliferation. Indeed, in contrast to the secondary responses of DC1- or DC2-primed CD8 T cells to the original alloantigen that respectively produce cytokine IFN-γ or IL-10, their responses to the third-party alloantigen produce neither IFN-γ, nor IL-10 during the 48 h of stimulation, a feature of primary response (Fig. 2 D). These data indicate that DC2 induce alloantigen-specific anergy of CD8 T cells, which display an impaired ability to mount cytolytic and secondary proliferative responses.


Generation of human CD8 T regulatory cells by CD40 ligand-activated plasmacytoid dendritic cells.

Gilliet M, Liu YJ - J. Exp. Med. (2002)

DC2-primed CD8 T cells exhibit poor cytolytic activity and are hyporesponsive to secondary restimulation. (A) CD8 T cells were primed for 6 d with DC1 (•, ▪) and DC2 (○, □), and collected and tested for their ability to lyse allogeneic (•, ○) or autologous (▪, □) B cells. The results represent six independent experiments. (B) CD8 T cells primed with DC1 and DC2 for 6 d were collected and restimulated with DC1 and DC2 derived from the donor used for priming. CD8 T cell expansion (upper panels), proliferation (middle panels), and increase in cell size (lower panel) were determined after 3 d of restimulation. Histograms represent CD8 T cell size before (filled) and after restimulation (open histograms). The results represent three independent experiments. (C) CD8 T cells from donor A were primed for 6 d with DC1 and DC2 from donor B, and then restimulated with DC1 from donor B or donor C. Proliferation was determined after 3 d of restimulation. (D) IFN-γ and IL-10 in the supernatants of CD8 T cells, restimulated as described in C for 2 d.
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Related In: Results  -  Collection

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fig2: DC2-primed CD8 T cells exhibit poor cytolytic activity and are hyporesponsive to secondary restimulation. (A) CD8 T cells were primed for 6 d with DC1 (•, ▪) and DC2 (○, □), and collected and tested for their ability to lyse allogeneic (•, ○) or autologous (▪, □) B cells. The results represent six independent experiments. (B) CD8 T cells primed with DC1 and DC2 for 6 d were collected and restimulated with DC1 and DC2 derived from the donor used for priming. CD8 T cell expansion (upper panels), proliferation (middle panels), and increase in cell size (lower panel) were determined after 3 d of restimulation. Histograms represent CD8 T cell size before (filled) and after restimulation (open histograms). The results represent three independent experiments. (C) CD8 T cells from donor A were primed for 6 d with DC1 and DC2 from donor B, and then restimulated with DC1 from donor B or donor C. Proliferation was determined after 3 d of restimulation. (D) IFN-γ and IL-10 in the supernatants of CD8 T cells, restimulated as described in C for 2 d.
Mentions: Whereas CD8 T cells primed by DC1 were potent cytotoxic effectors lysing allogeneic targets at low E/T ratios, CD8 T cells primed with DC2 displayed poor alloantigen-specific cytotoxicity (Fig. 2 A), but expressed similar levels of perforin and granzyme B (unpublished data). In addition, CD8 T cells primed with DC1 responded strongly to secondary restimulation with allogeneic DC1 or DC2, whereas CD8 T cells primed with DC2 were hyporesponsive to secondary restimulation with DC1 or DC2, as determined by proliferation and blastogenesis (Fig. 2 B). However, DC2-primed CD8 T cells were able to mount a proliferative response to third-party alloantigens (Fig. 2 C). This is because in contrast to previously described IL-10–producing Tr1 cell clones that display the same allo-specificity (7), DC2-primed CD8 T cells derived from a 6-d primary cell culture not only contain antigen-specific anergic CD8 T cells, but also unprimed naive T cells with other specificities. Therefore, upon restimulation with the original alloantigen, DC2-primed anergic CD8 T cells will not proliferate, whereas unprimed CD8 T cells specific to the third-party alloantigen will undergo primary proliferation. Indeed, in contrast to the secondary responses of DC1- or DC2-primed CD8 T cells to the original alloantigen that respectively produce cytokine IFN-γ or IL-10, their responses to the third-party alloantigen produce neither IFN-γ, nor IL-10 during the 48 h of stimulation, a feature of primary response (Fig. 2 D). These data indicate that DC2 induce alloantigen-specific anergy of CD8 T cells, which display an impaired ability to mount cytolytic and secondary proliferative responses.

Bottom Line: Unlike DC1-primed CD8 T cells that produced large amounts of interferon (IFN)-gamma upon restimulation, DC2-primed CD8 T cells produced significant amounts of interleukin (IL)-10, low IFN-gamma, and no IL-4, IL-5, nor transforming growth factor (TGF)-beta.This inhibition was mediated by IL-10, but not by TGF-beta.IL-10-producing CD8 T cells could not inhibit the proliferation of DC1-preactivated effector T cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, DNAX Research Institute of Molecular and Cellular Biology, 901 California Avenue, Palo Alto, CA 94304, USA.

ABSTRACT
Although CD8 T cell-mediated immunosuppression has been a well-known phenomenon during the last three decades, the nature of primary CD8 T suppressor cells and the mechanism underlying their generation remain enigmatic. We demonstrated that naive CD8 T cells primed with allogeneic CD40 ligand-activated plasmacytoid dendritic cells (DC)2 differentiated into CD8 T cells that displayed poor secondary proliferative and cytolytic responses. By contrast, naive CD8 T cells primed with allogeneic CD40 ligand-activated monocyte-derived DCs (DC1) differentiated into CD8 T cells, which proliferated to secondary stimulation and killed allogeneic target cells. Unlike DC1-primed CD8 T cells that produced large amounts of interferon (IFN)-gamma upon restimulation, DC2-primed CD8 T cells produced significant amounts of interleukin (IL)-10, low IFN-gamma, and no IL-4, IL-5, nor transforming growth factor (TGF)-beta. The addition of anti-IL-10-neutralizing monoclonal antibodies during DC2 and CD8 T cell coculture, completely blocked the generation of IL-10-producing anergic CD8 T cells. IL-10-producing CD8 T cells strongly inhibit the allospecific proliferation of naive CD8 T cells to monocytes, and mature and immature DCs. This inhibition was mediated by IL-10, but not by TGF-beta. IL-10-producing CD8 T cells could inhibit the bystander proliferation of naive CD8 T cells, provided that they were restimulated nearby to produce IL-10. IL-10-producing CD8 T cells could not inhibit the proliferation of DC1-preactivated effector T cells. This study demonstrates that IL-10-producing CD8 T cells are regulatory T cells, which provides a cellular basis for the phenomenon of CD8 T cell-mediated immunosuppression and suggests a role for plasmacytoid DC2 in immunological tolerance.

Show MeSH
Related in: MedlinePlus