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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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Phenotypic analysis of IL-10– and IFN-γ–producing CD4+ T lymphocytes freshly isolated from mice with acute T. gondii infection. Peritoneal and spleen lymphocytes were recovered from day 7–infected and uninfected control mice. (A) IL-10 and IFN-γ ICS of these populations (pooled from three animals) after restimulation for 5 h with anti-CD3 mAb. The dot plots shown were gated on CD4+ cells and are representative of five experiments performed. (B) Frequency of Foxp3+ or T-bet+ CD4+ T lymphocytes in the spleen and peritoneum of naive versus day 7–infected mice. Bars represent the mean ± SD of assays on the individual animals (n = 3–5). (C) T-bet versus IL-10 expression in peritoneal IFN-γ+ CD4+ T cells recovered from infected mice and restimulated as in A. (D) Frequency of peritoneal IL-10+ CD4+ T lymphocytes within the IFN-γ+T-bet+ and IFN-γ−T-bet− populations in naive versus day 7–infected mice. Bars represent the mean ± SD of assays on the individual animals (n = 3). The data shown in C and D are representative of three experiments performed.
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fig5: Phenotypic analysis of IL-10– and IFN-γ–producing CD4+ T lymphocytes freshly isolated from mice with acute T. gondii infection. Peritoneal and spleen lymphocytes were recovered from day 7–infected and uninfected control mice. (A) IL-10 and IFN-γ ICS of these populations (pooled from three animals) after restimulation for 5 h with anti-CD3 mAb. The dot plots shown were gated on CD4+ cells and are representative of five experiments performed. (B) Frequency of Foxp3+ or T-bet+ CD4+ T lymphocytes in the spleen and peritoneum of naive versus day 7–infected mice. Bars represent the mean ± SD of assays on the individual animals (n = 3–5). (C) T-bet versus IL-10 expression in peritoneal IFN-γ+ CD4+ T cells recovered from infected mice and restimulated as in A. (D) Frequency of peritoneal IL-10+ CD4+ T lymphocytes within the IFN-γ+T-bet+ and IFN-γ−T-bet− populations in naive versus day 7–infected mice. Bars represent the mean ± SD of assays on the individual animals (n = 3). The data shown in C and D are representative of three experiments performed.

Mentions: The above experiments involved cytokine measurements on lymphocytes restimulated in vitro with parasite Ag. To address whether IL-10+IFN-γ+ CD4+ T cells are also the major source of IL-10 in vivo, we performed ICS on CD4 T lymphocytes from acutely infected mice ex vivo, where the frequency of activated CD44highCD62Llow CD4+ T cells exceeds 70 and 50% in the peritoneum and spleen, respectively (unpublished data). As shown in Fig. 5 A, IL-10+ IFN-γ+ double-producing cells represented the dominant IL-10+ population present in peritoneum and spleen at day 7 after infection and constituted on average 10% of the total IFN-γ+ CD4+ T cells. This population was also found to predominate in the splenic CD4 T cell response to a second intracellular protozoan parasite, Trypanosoma cruzi (Fig. S1, available at http://www.jem.org/cgi/content/full/jem.20062175/DC1).


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)

Phenotypic analysis of IL-10– and IFN-γ–producing CD4+ T lymphocytes freshly isolated from mice with acute T. gondii infection. Peritoneal and spleen lymphocytes were recovered from day 7–infected and uninfected control mice. (A) IL-10 and IFN-γ ICS of these populations (pooled from three animals) after restimulation for 5 h with anti-CD3 mAb. The dot plots shown were gated on CD4+ cells and are representative of five experiments performed. (B) Frequency of Foxp3+ or T-bet+ CD4+ T lymphocytes in the spleen and peritoneum of naive versus day 7–infected mice. Bars represent the mean ± SD of assays on the individual animals (n = 3–5). (C) T-bet versus IL-10 expression in peritoneal IFN-γ+ CD4+ T cells recovered from infected mice and restimulated as in A. (D) Frequency of peritoneal IL-10+ CD4+ T lymphocytes within the IFN-γ+T-bet+ and IFN-γ−T-bet− populations in naive versus day 7–infected mice. Bars represent the mean ± SD of assays on the individual animals (n = 3). The data shown in C and D are representative of three experiments performed.
© Copyright Policy
Related In: Results  -  Collection

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

fig5: Phenotypic analysis of IL-10– and IFN-γ–producing CD4+ T lymphocytes freshly isolated from mice with acute T. gondii infection. Peritoneal and spleen lymphocytes were recovered from day 7–infected and uninfected control mice. (A) IL-10 and IFN-γ ICS of these populations (pooled from three animals) after restimulation for 5 h with anti-CD3 mAb. The dot plots shown were gated on CD4+ cells and are representative of five experiments performed. (B) Frequency of Foxp3+ or T-bet+ CD4+ T lymphocytes in the spleen and peritoneum of naive versus day 7–infected mice. Bars represent the mean ± SD of assays on the individual animals (n = 3–5). (C) T-bet versus IL-10 expression in peritoneal IFN-γ+ CD4+ T cells recovered from infected mice and restimulated as in A. (D) Frequency of peritoneal IL-10+ CD4+ T lymphocytes within the IFN-γ+T-bet+ and IFN-γ−T-bet− populations in naive versus day 7–infected mice. Bars represent the mean ± SD of assays on the individual animals (n = 3). The data shown in C and D are representative of three experiments performed.
Mentions: The above experiments involved cytokine measurements on lymphocytes restimulated in vitro with parasite Ag. To address whether IL-10+IFN-γ+ CD4+ T cells are also the major source of IL-10 in vivo, we performed ICS on CD4 T lymphocytes from acutely infected mice ex vivo, where the frequency of activated CD44highCD62Llow CD4+ T cells exceeds 70 and 50% in the peritoneum and spleen, respectively (unpublished data). As shown in Fig. 5 A, IL-10+ IFN-γ+ double-producing cells represented the dominant IL-10+ population present in peritoneum and spleen at day 7 after infection and constituted on average 10% of the total IFN-γ+ CD4+ T cells. This population was also found to predominate in the splenic CD4 T cell response to a second intracellular protozoan parasite, Trypanosoma cruzi (Fig. S1, available at http://www.jem.org/cgi/content/full/jem.20062175/DC1).

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