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Conventional T-bet(+)Foxp3(-) Th1 cells are the major source of host-protective regulatory IL-10 during intracellular protozoan infection.

Jankovic D, Kullberg MC, Feng CG, Goldszmid RS, Collazo CM, Wilson M, Wynn TA, Kamanaka M, Flavell RA, Sher A - J. Exp. Med. (2007)

Bottom Line: Unexpectedly, IFN-gamma-secreting T-bet(+)Foxp3(-) T helper type 1 (Th1) cells were found to be the major producers of IL-10 in these animals.Further analysis revealed that the same IL-10(+)IFN-gamma(gamma) population displayed potent effector function against the parasite while, paradoxically, also inducing profound suppression of IL-12 production by antigen-presenting cells.These findings indicate that IL-10 production by CD4(+) T lymphocytes need not involve a distinct regulatory Th cell subset but can be generated in Th1 cells as part of the effector response to intracellular pathogens.

View Article: PubMed Central - PubMed

Affiliation: Immunobiology Section and 2Immunopathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. DJankovic@niaid.nih.gov

ABSTRACT
Although interferon gamma (IFN-gamma) secretion is essential for control of most intracellular pathogens, host survival often also depends on the expression of interleukin 10 (IL-10), a cytokine known to counteract IFN-gamma effector functions. We analyzed the source of regulatory IL-10 in mice infected with the protozoan parasite Toxoplasma gondii. Unexpectedly, IFN-gamma-secreting T-bet(+)Foxp3(-) T helper type 1 (Th1) cells were found to be the major producers of IL-10 in these animals. Further analysis revealed that the same IL-10(+)IFN-gamma(gamma) population displayed potent effector function against the parasite while, paradoxically, also inducing profound suppression of IL-12 production by antigen-presenting cells. Although at any given time point only a fraction of the cells appeared to simultaneously produce IL-10 and IFN-gamma, IL-10 production could be stimulated in IL-10(-)IFN-gamma(+) cells by further activation in vitro. In addition, experiments with T. gondii-specific IL-10(+)IFN-gamma(+) CD4 clones revealed that although IFN-gamma expression is imprinted and triggered with similar kinetics regardless of the state of Th1 cell activation, IL-10 secretion is induced more rapidly from recently activated than from resting cells. These findings indicate that IL-10 production by CD4(+) T lymphocytes need not involve a distinct regulatory Th cell subset but can be generated in Th1 cells as part of the effector response to intracellular pathogens.

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In vitro induction of IL-10 expression in IL-10− CD4+ T cells from infected mice. CD4+CD44+ GFP− lymphocytes were purified by FACS from peritoneum and spleen of day 7–infected IL-10 GFP knock-in tiger mice (n = 2–3) and cultured in medium alone or in the presence of anti-CD3 mAb. Control cultures consisted of anti-CD3–stimulated CD4+ T cells isolated from uninfected tiger mice. Induction of GFP expression was examined at 24 h after initiation of cultures and at 48 h for splenic population from infected animals. The results shown are representative of two experiments performed.
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fig7: In vitro induction of IL-10 expression in IL-10− CD4+ T cells from infected mice. CD4+CD44+ GFP− lymphocytes were purified by FACS from peritoneum and spleen of day 7–infected IL-10 GFP knock-in tiger mice (n = 2–3) and cultured in medium alone or in the presence of anti-CD3 mAb. Control cultures consisted of anti-CD3–stimulated CD4+ T cells isolated from uninfected tiger mice. Induction of GFP expression was examined at 24 h after initiation of cultures and at 48 h for splenic population from infected animals. The results shown are representative of two experiments performed.

Mentions: We next asked whether the IL-10+IFN-γ+ and IL-10−IFN-γ+ CD4 T cells induced by T. gondii infection are discrete, phenotypically stable subsets or represent different steps in the Th1 cell differentiation pathway. To do so, we isolated GFP/IL-10+ and GFP/IL-10− CD4+CD44high lymphocytes from acutely infected tiger mice (as described in Fig. 6 A) and restimulated both populations in vitro with plate-bound anti-CD3 mAb. When measured by FACS, GFP expression was gradually acquired in the cultures initially containing GFP/IL-10− CD4+ T cells, reaching ∼20% of the population by 24 and 48 h for the peritoneal and splenic populations, respectively (Fig. 7). The appearance of GFP+ cells correlated with the induction of IL-10 secretion as measured by ELISA, and parallel analysis of splenic GFP/IL-10− CD4+ T cells by ICS both confirmed the appearance of IL-10+ lymphocytes and demonstrated that these cells coexpress IFN-γ (not depicted). In control experiments, no induction of GFP expression was observed in anti-CD3–stimulated CD4+ cells from uninfected animals, confirming the requirement for in vivo priming (Fig. 7). Furthermore, no changes in GFP expression were observed when the GFP/IL-10+ CD4+CD44high population was subjected to the same in vitro stimulation (not depicted).


Conventional T-bet(+)Foxp3(-) Th1 cells are the major source of host-protective regulatory IL-10 during intracellular protozoan infection.

Jankovic D, Kullberg MC, Feng CG, Goldszmid RS, Collazo CM, Wilson M, Wynn TA, Kamanaka M, Flavell RA, Sher A - J. Exp. Med. (2007)

In vitro induction of IL-10 expression in IL-10− CD4+ T cells from infected mice. CD4+CD44+ GFP− lymphocytes were purified by FACS from peritoneum and spleen of day 7–infected IL-10 GFP knock-in tiger mice (n = 2–3) and cultured in medium alone or in the presence of anti-CD3 mAb. Control cultures consisted of anti-CD3–stimulated CD4+ T cells isolated from uninfected tiger mice. Induction of GFP expression was examined at 24 h after initiation of cultures and at 48 h for splenic population from infected animals. The results shown are representative of two experiments performed.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2118735&req=5

fig7: In vitro induction of IL-10 expression in IL-10− CD4+ T cells from infected mice. CD4+CD44+ GFP− lymphocytes were purified by FACS from peritoneum and spleen of day 7–infected IL-10 GFP knock-in tiger mice (n = 2–3) and cultured in medium alone or in the presence of anti-CD3 mAb. Control cultures consisted of anti-CD3–stimulated CD4+ T cells isolated from uninfected tiger mice. Induction of GFP expression was examined at 24 h after initiation of cultures and at 48 h for splenic population from infected animals. The results shown are representative of two experiments performed.
Mentions: We next asked whether the IL-10+IFN-γ+ and IL-10−IFN-γ+ CD4 T cells induced by T. gondii infection are discrete, phenotypically stable subsets or represent different steps in the Th1 cell differentiation pathway. To do so, we isolated GFP/IL-10+ and GFP/IL-10− CD4+CD44high lymphocytes from acutely infected tiger mice (as described in Fig. 6 A) and restimulated both populations in vitro with plate-bound anti-CD3 mAb. When measured by FACS, GFP expression was gradually acquired in the cultures initially containing GFP/IL-10− CD4+ T cells, reaching ∼20% of the population by 24 and 48 h for the peritoneal and splenic populations, respectively (Fig. 7). The appearance of GFP+ cells correlated with the induction of IL-10 secretion as measured by ELISA, and parallel analysis of splenic GFP/IL-10− CD4+ T cells by ICS both confirmed the appearance of IL-10+ lymphocytes and demonstrated that these cells coexpress IFN-γ (not depicted). In control experiments, no induction of GFP expression was observed in anti-CD3–stimulated CD4+ cells from uninfected animals, confirming the requirement for in vivo priming (Fig. 7). Furthermore, no changes in GFP expression were observed when the GFP/IL-10+ CD4+CD44high population was subjected to the same in vitro stimulation (not depicted).

Bottom Line: Unexpectedly, IFN-gamma-secreting T-bet(+)Foxp3(-) T helper type 1 (Th1) cells were found to be the major producers of IL-10 in these animals.Further analysis revealed that the same IL-10(+)IFN-gamma(gamma) population displayed potent effector function against the parasite while, paradoxically, also inducing profound suppression of IL-12 production by antigen-presenting cells.These findings indicate that IL-10 production by CD4(+) T lymphocytes need not involve a distinct regulatory Th cell subset but can be generated in Th1 cells as part of the effector response to intracellular pathogens.

View Article: PubMed Central - PubMed

Affiliation: Immunobiology Section and 2Immunopathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. DJankovic@niaid.nih.gov

ABSTRACT
Although interferon gamma (IFN-gamma) secretion is essential for control of most intracellular pathogens, host survival often also depends on the expression of interleukin 10 (IL-10), a cytokine known to counteract IFN-gamma effector functions. We analyzed the source of regulatory IL-10 in mice infected with the protozoan parasite Toxoplasma gondii. Unexpectedly, IFN-gamma-secreting T-bet(+)Foxp3(-) T helper type 1 (Th1) cells were found to be the major producers of IL-10 in these animals. Further analysis revealed that the same IL-10(+)IFN-gamma(gamma) population displayed potent effector function against the parasite while, paradoxically, also inducing profound suppression of IL-12 production by antigen-presenting cells. Although at any given time point only a fraction of the cells appeared to simultaneously produce IL-10 and IFN-gamma, IL-10 production could be stimulated in IL-10(-)IFN-gamma(+) cells by further activation in vitro. In addition, experiments with T. gondii-specific IL-10(+)IFN-gamma(+) CD4 clones revealed that although IFN-gamma expression is imprinted and triggered with similar kinetics regardless of the state of Th1 cell activation, IL-10 secretion is induced more rapidly from recently activated than from resting cells. These findings indicate that IL-10 production by CD4(+) T lymphocytes need not involve a distinct regulatory Th cell subset but can be generated in Th1 cells as part of the effector response to intracellular pathogens.

Show MeSH
Related in: MedlinePlus