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T cell-intrinsic role of Nod2 in promoting type 1 immunity to Toxoplasma gondii.

Shaw MH, Reimer T, Sánchez-Valdepeñas C, Warner N, Kim YG, Fresno M, Nuñez G - Nat. Immunol. (2009)

Bottom Line: Nod2 deficiency results in an impaired immune response to bacterial pathogens.Nod2(-/-) CD4(+) T cells had poor helper T cell differentiation, which was associated with impaired production of interleukin 2 (IL-2) and nuclear accumulation of the transcription factor subunit c-Rel.Our data demonstrate a T cell-intrinsic role for Nod2 signaling that is critical for host defense against T. gondii.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.

ABSTRACT
Nod2 belongs to the nucleotide-binding oligomerization domain receptor (NLR) family of proteins, which function as intracellular pathogen sensors in innate immune cells. Nod2 deficiency results in an impaired immune response to bacterial pathogens. However, how this protein promotes host defense against intracellular parasites is unknown. Here we found that Nod2(-/-) mice had less clearance of Toxoplasma gondii and lower interferon-gamma (IFN-gamma) production. Reconstitution of T cell-deficient mice with Nod2(-/-) T cells followed by T. gondii infection demonstrated a T cell-intrinsic defect. Nod2(-/-) CD4(+) T cells had poor helper T cell differentiation, which was associated with impaired production of interleukin 2 (IL-2) and nuclear accumulation of the transcription factor subunit c-Rel. Our data demonstrate a T cell-intrinsic role for Nod2 signaling that is critical for host defense against T. gondii.

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DC function during T. gondii infection is unaffected in the absence of Nod2. (a) Left, FACs sorted CD4+ T cells from the peritoneal cavity of day 9 CPS-immunized wild-type and Nod2−/− mice were stimulated for 6 h with or without wild-type or Nod2−/− BMDCs that were infected with T. gondii. IFN-γ production was measured by flow cytometry. Each dot-plot is gated on CD4+TCR-β+ cells and is from one representative mouse per group (n = 3–4 mice per group). Right, data were pooled; each dot represents one mouse and horizontal bars represent the mean. (b) IFN-γ secretion by peritoneal CD4+ cells was determined as described in (a), but cells were restimulated for 24 h in vitro. (c) Left, MACS-sorted splenic CD4+ cells from naïve wild-type (Thy-1.1) mice were injected intravenously into wild-type (Thy-1.2) or Nod2−/− (Thy-1.2) recipients, which were then challenged i.p. with irradiated CPS parasite. On day 9 post-infection, PECs were isolated and IFN-γ production by donor CD4 cells was determined by intracellular cytokine staining (left; dot plots were gated on CD4+TCRβ+Thy-1.1+ cells). Right, the data were pooled; each dot represents one mouse and horizontal bars represent the mean.
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Figure 4: DC function during T. gondii infection is unaffected in the absence of Nod2. (a) Left, FACs sorted CD4+ T cells from the peritoneal cavity of day 9 CPS-immunized wild-type and Nod2−/− mice were stimulated for 6 h with or without wild-type or Nod2−/− BMDCs that were infected with T. gondii. IFN-γ production was measured by flow cytometry. Each dot-plot is gated on CD4+TCR-β+ cells and is from one representative mouse per group (n = 3–4 mice per group). Right, data were pooled; each dot represents one mouse and horizontal bars represent the mean. (b) IFN-γ secretion by peritoneal CD4+ cells was determined as described in (a), but cells were restimulated for 24 h in vitro. (c) Left, MACS-sorted splenic CD4+ cells from naïve wild-type (Thy-1.1) mice were injected intravenously into wild-type (Thy-1.2) or Nod2−/− (Thy-1.2) recipients, which were then challenged i.p. with irradiated CPS parasite. On day 9 post-infection, PECs were isolated and IFN-γ production by donor CD4 cells was determined by intracellular cytokine staining (left; dot plots were gated on CD4+TCRβ+Thy-1.1+ cells). Right, the data were pooled; each dot represents one mouse and horizontal bars represent the mean.

Mentions: DCs play a major role in T cell priming and promoting IL-12-driven TH1 immunity against T. gondii11. Therefore, the defective T cell response seen in Nod2-deficient mice could be due to impaired DC function. To evaluate whether Nod2−/− DCs have functional defects in processing and presenting T. gondii antigen, T. gondii-infected wild-type and Nod2-deficient bone marrow-derived DCs (BMDCs) were used to stimulate FACS purified peritoneal CD4+ T lymphocytes derived from day 9 CPS immunized wild-type or Nod2−/− animals. Both Nod2−/− and wild-type BMDCs efficiently induced IFN-γ expression in wild-type CD4+ T cells (Fig. 4a). Interestingly, IFN-γ production by Nod2−/− CD4+ T cells remained attenuated, even in the presence of wild-type DCs. Consistent with the flow cytometry analysis, ex vivo cultures containing Nod2-deficient CD4+ cells secreted reduced quantities of IFN-γ when stimulated with parasite-infected wild-type or Nod2−/− BMDCs (Figure 4b). To confirm that the blunted T cell response observed in Nod2−/− mice is not due to impaired antigen presentation and/or T cell priming by Nod2−/− DCs, wild-type (Thy-1.1+) CD4+ T cells were adoptively transferred into wild-type or Nod2−/− recipient mice. These chimaeras were then immunized with T. gondii. Similar frequencies of donor (Thy-1.1+) IFN-γ+ CD4+ T cells were observed in wild-type and Nod2−/− recipients of wild-type T cells (Fig. 4c). Collectively, these findings argue that Nod2−/− DCs are functionally normal during T. gondii infection and suggest that Nod2 functions in a T cell- intrinsic manner to promote optimal TH1 immunity against T. gondii.


T cell-intrinsic role of Nod2 in promoting type 1 immunity to Toxoplasma gondii.

Shaw MH, Reimer T, Sánchez-Valdepeñas C, Warner N, Kim YG, Fresno M, Nuñez G - Nat. Immunol. (2009)

DC function during T. gondii infection is unaffected in the absence of Nod2. (a) Left, FACs sorted CD4+ T cells from the peritoneal cavity of day 9 CPS-immunized wild-type and Nod2−/− mice were stimulated for 6 h with or without wild-type or Nod2−/− BMDCs that were infected with T. gondii. IFN-γ production was measured by flow cytometry. Each dot-plot is gated on CD4+TCR-β+ cells and is from one representative mouse per group (n = 3–4 mice per group). Right, data were pooled; each dot represents one mouse and horizontal bars represent the mean. (b) IFN-γ secretion by peritoneal CD4+ cells was determined as described in (a), but cells were restimulated for 24 h in vitro. (c) Left, MACS-sorted splenic CD4+ cells from naïve wild-type (Thy-1.1) mice were injected intravenously into wild-type (Thy-1.2) or Nod2−/− (Thy-1.2) recipients, which were then challenged i.p. with irradiated CPS parasite. On day 9 post-infection, PECs were isolated and IFN-γ production by donor CD4 cells was determined by intracellular cytokine staining (left; dot plots were gated on CD4+TCRβ+Thy-1.1+ cells). Right, the data were pooled; each dot represents one mouse and horizontal bars represent the mean.
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Figure 4: DC function during T. gondii infection is unaffected in the absence of Nod2. (a) Left, FACs sorted CD4+ T cells from the peritoneal cavity of day 9 CPS-immunized wild-type and Nod2−/− mice were stimulated for 6 h with or without wild-type or Nod2−/− BMDCs that were infected with T. gondii. IFN-γ production was measured by flow cytometry. Each dot-plot is gated on CD4+TCR-β+ cells and is from one representative mouse per group (n = 3–4 mice per group). Right, data were pooled; each dot represents one mouse and horizontal bars represent the mean. (b) IFN-γ secretion by peritoneal CD4+ cells was determined as described in (a), but cells were restimulated for 24 h in vitro. (c) Left, MACS-sorted splenic CD4+ cells from naïve wild-type (Thy-1.1) mice were injected intravenously into wild-type (Thy-1.2) or Nod2−/− (Thy-1.2) recipients, which were then challenged i.p. with irradiated CPS parasite. On day 9 post-infection, PECs were isolated and IFN-γ production by donor CD4 cells was determined by intracellular cytokine staining (left; dot plots were gated on CD4+TCRβ+Thy-1.1+ cells). Right, the data were pooled; each dot represents one mouse and horizontal bars represent the mean.
Mentions: DCs play a major role in T cell priming and promoting IL-12-driven TH1 immunity against T. gondii11. Therefore, the defective T cell response seen in Nod2-deficient mice could be due to impaired DC function. To evaluate whether Nod2−/− DCs have functional defects in processing and presenting T. gondii antigen, T. gondii-infected wild-type and Nod2-deficient bone marrow-derived DCs (BMDCs) were used to stimulate FACS purified peritoneal CD4+ T lymphocytes derived from day 9 CPS immunized wild-type or Nod2−/− animals. Both Nod2−/− and wild-type BMDCs efficiently induced IFN-γ expression in wild-type CD4+ T cells (Fig. 4a). Interestingly, IFN-γ production by Nod2−/− CD4+ T cells remained attenuated, even in the presence of wild-type DCs. Consistent with the flow cytometry analysis, ex vivo cultures containing Nod2-deficient CD4+ cells secreted reduced quantities of IFN-γ when stimulated with parasite-infected wild-type or Nod2−/− BMDCs (Figure 4b). To confirm that the blunted T cell response observed in Nod2−/− mice is not due to impaired antigen presentation and/or T cell priming by Nod2−/− DCs, wild-type (Thy-1.1+) CD4+ T cells were adoptively transferred into wild-type or Nod2−/− recipient mice. These chimaeras were then immunized with T. gondii. Similar frequencies of donor (Thy-1.1+) IFN-γ+ CD4+ T cells were observed in wild-type and Nod2−/− recipients of wild-type T cells (Fig. 4c). Collectively, these findings argue that Nod2−/− DCs are functionally normal during T. gondii infection and suggest that Nod2 functions in a T cell- intrinsic manner to promote optimal TH1 immunity against T. gondii.

Bottom Line: Nod2 deficiency results in an impaired immune response to bacterial pathogens.Nod2(-/-) CD4(+) T cells had poor helper T cell differentiation, which was associated with impaired production of interleukin 2 (IL-2) and nuclear accumulation of the transcription factor subunit c-Rel.Our data demonstrate a T cell-intrinsic role for Nod2 signaling that is critical for host defense against T. gondii.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan, USA.

ABSTRACT
Nod2 belongs to the nucleotide-binding oligomerization domain receptor (NLR) family of proteins, which function as intracellular pathogen sensors in innate immune cells. Nod2 deficiency results in an impaired immune response to bacterial pathogens. However, how this protein promotes host defense against intracellular parasites is unknown. Here we found that Nod2(-/-) mice had less clearance of Toxoplasma gondii and lower interferon-gamma (IFN-gamma) production. Reconstitution of T cell-deficient mice with Nod2(-/-) T cells followed by T. gondii infection demonstrated a T cell-intrinsic defect. Nod2(-/-) CD4(+) T cells had poor helper T cell differentiation, which was associated with impaired production of interleukin 2 (IL-2) and nuclear accumulation of the transcription factor subunit c-Rel. Our data demonstrate a T cell-intrinsic role for Nod2 signaling that is critical for host defense against T. gondii.

Show MeSH
Related in: MedlinePlus