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IFNγ and IL-12 Restrict Th2 Responses during Helminth/Plasmodium Co-Infection and Promote IFNγ from Th2 Cells.

Coomes SM, Pelly VS, Kannan Y, Okoye IS, Czieso S, Entwistle LJ, Perez-Lloret J, Nikolov N, Potocnik AJ, Biró J, Langhorne J, Wilson MS - PLoS Pathog. (2015)

Bottom Line: Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines.Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells.In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom.

ABSTRACT
Parasitic helminths establish chronic infections in mammalian hosts. Helminth/Plasmodium co-infections occur frequently in endemic areas. However, it is unclear whether Plasmodium infections compromise anti-helminth immunity, contributing to the chronicity of infection. Immunity to Plasmodium or helminths requires divergent CD4+ T cell-driven responses, dominated by IFNγ or IL-4, respectively. Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines. Whether such plasticity occurs during co-infection is unclear. In this study, we observed reduced anti-helminth Th2 cell responses and compromised anti-helminth immunity during Heligmosomoides polygyrus and Plasmodium chabaudi co-infection. Using newly established triple cytokine reporter mice (Il4gfpIfngyfpIl17aFP635), we demonstrated that Il4gfp+ Th2 cells purified from in vitro cultures or isolated ex vivo from helminth-infected mice up-regulated IFNγ following adoptive transfer into Rag1-/- mice infected with P. chabaudi. Functionally, Th2 cells that up-regulated IFNγ were transcriptionally re-wired and protected recipient mice from high parasitemia. Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells. Finally, blockade of IL-12 and IFNγ during co-infection partially preserved anti-helminth Th2 responses. In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection. Consequently, co-infection with Plasmodium spp. may contribute to the chronicity of helminth infection by reducing anti-helminth Th2 cells and converting them into IFNγ-secreting cells.

No MeSH data available.


Related in: MedlinePlus

Th2 cells become IL-12 responsive following adoptive transfer.A and B). CD4+Il4gfp+in vitro Th2 cells or naïve CD4 cells were transferred to Rag1–/–mice for 2 weeks. CD4+TCRβ+ cells were then sorted from spleens of recipient mice and treated with 10ng/mL IL-12 for 15 minutes (blue) (or untreated, red) and then stained for pSTAT4 by FACS. Representative of 2 independent experiments. C—G). Naïve CD4+ T cells or in vitro Th2 cells (CD4+TCRβ+Il4gfp+Ifngyfp-Il17aFP635-) were transferred to Rag1–/–recipient mice for 14 days. Mice were infected with P. chabaudi and harvested at day 8 post-infection. Mice were treated i.p. with 0.5mg of anti-IL12 at days -1, 6, 13, and 19. D–F). Cytokine reporter expression in transferred cells in the spleen, with or without anti-IL-12 treatment. G). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. Data are representative of 2 independent experiments with 3–6 mice per group. * denotes P<0.05.
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ppat.1004994.g007: Th2 cells become IL-12 responsive following adoptive transfer.A and B). CD4+Il4gfp+in vitro Th2 cells or naïve CD4 cells were transferred to Rag1–/–mice for 2 weeks. CD4+TCRβ+ cells were then sorted from spleens of recipient mice and treated with 10ng/mL IL-12 for 15 minutes (blue) (or untreated, red) and then stained for pSTAT4 by FACS. Representative of 2 independent experiments. C—G). Naïve CD4+ T cells or in vitro Th2 cells (CD4+TCRβ+Il4gfp+Ifngyfp-Il17aFP635-) were transferred to Rag1–/–recipient mice for 14 days. Mice were infected with P. chabaudi and harvested at day 8 post-infection. Mice were treated i.p. with 0.5mg of anti-IL12 at days -1, 6, 13, and 19. D–F). Cytokine reporter expression in transferred cells in the spleen, with or without anti-IL-12 treatment. G). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. Data are representative of 2 independent experiments with 3–6 mice per group. * denotes P<0.05.

Mentions: From our RNA-Seq analysis we also identified that the canonical Th1 differentiating cytokines, IL-12 and IFNγ, may be responsible for the transcriptional profile observed in our converted cells (Fig 3E). We first tested whether Th2 cells were responsive to IL-12 by measuring the phosphorylation of STAT4 following exposure to IL-12. Supporting previous studies [45–47], neither naïve CD4+ T cells nor sorted Il4gfp+ Th2 cells phosphorylated STAT4 in response to IL-12 (Fig 7A and 7B; Pre- transfer). We then sorted transferred cells from naïve CD4+ T cell or Il4gfp+ Th2 cell recipient Rag1–/–mice 2 weeks post-transfer and found that both populations were responsive to IL-12 (Fig 7A and 7B; Post-transfer). Thus, it was possible that IL-12 was promoting IFNγ expression in Th2 cells following P. chabaudi infection. We tested the role of IL-12 by transferring naïve or Il4gfp+ Th2 cells to Rag1–/–mice and blocking IL-12 prior to and after P. chabaudi infection (Fig 7C). Blocking IL-12 reduced expression of Ifngyfp in naïve T cells (reduced from 78.9% to 52.61%); however, IL-12 blockade did not substantially alter the frequency of Ifngyfp+ cells derived from Th2 cells. Instead, IL-12 blockade maintained expression of Il4gfp+ in the Th2 population, with significantly larger Il4gfp+ and Il4gfp+Ifngyfp+ populations (Fig 7D–7F). These data indicate that in this system IL-12 down-regulated Il4gfp expression, but was not required for IFNγ from Th2 cells. Furthermore, neutralization of IL-12 did not impact parasitemia (Fig 7G).


IFNγ and IL-12 Restrict Th2 Responses during Helminth/Plasmodium Co-Infection and Promote IFNγ from Th2 Cells.

Coomes SM, Pelly VS, Kannan Y, Okoye IS, Czieso S, Entwistle LJ, Perez-Lloret J, Nikolov N, Potocnik AJ, Biró J, Langhorne J, Wilson MS - PLoS Pathog. (2015)

Th2 cells become IL-12 responsive following adoptive transfer.A and B). CD4+Il4gfp+in vitro Th2 cells or naïve CD4 cells were transferred to Rag1–/–mice for 2 weeks. CD4+TCRβ+ cells were then sorted from spleens of recipient mice and treated with 10ng/mL IL-12 for 15 minutes (blue) (or untreated, red) and then stained for pSTAT4 by FACS. Representative of 2 independent experiments. C—G). Naïve CD4+ T cells or in vitro Th2 cells (CD4+TCRβ+Il4gfp+Ifngyfp-Il17aFP635-) were transferred to Rag1–/–recipient mice for 14 days. Mice were infected with P. chabaudi and harvested at day 8 post-infection. Mice were treated i.p. with 0.5mg of anti-IL12 at days -1, 6, 13, and 19. D–F). Cytokine reporter expression in transferred cells in the spleen, with or without anti-IL-12 treatment. G). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. Data are representative of 2 independent experiments with 3–6 mice per group. * denotes P<0.05.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4493106&req=5

ppat.1004994.g007: Th2 cells become IL-12 responsive following adoptive transfer.A and B). CD4+Il4gfp+in vitro Th2 cells or naïve CD4 cells were transferred to Rag1–/–mice for 2 weeks. CD4+TCRβ+ cells were then sorted from spleens of recipient mice and treated with 10ng/mL IL-12 for 15 minutes (blue) (or untreated, red) and then stained for pSTAT4 by FACS. Representative of 2 independent experiments. C—G). Naïve CD4+ T cells or in vitro Th2 cells (CD4+TCRβ+Il4gfp+Ifngyfp-Il17aFP635-) were transferred to Rag1–/–recipient mice for 14 days. Mice were infected with P. chabaudi and harvested at day 8 post-infection. Mice were treated i.p. with 0.5mg of anti-IL12 at days -1, 6, 13, and 19. D–F). Cytokine reporter expression in transferred cells in the spleen, with or without anti-IL-12 treatment. G). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. Data are representative of 2 independent experiments with 3–6 mice per group. * denotes P<0.05.
Mentions: From our RNA-Seq analysis we also identified that the canonical Th1 differentiating cytokines, IL-12 and IFNγ, may be responsible for the transcriptional profile observed in our converted cells (Fig 3E). We first tested whether Th2 cells were responsive to IL-12 by measuring the phosphorylation of STAT4 following exposure to IL-12. Supporting previous studies [45–47], neither naïve CD4+ T cells nor sorted Il4gfp+ Th2 cells phosphorylated STAT4 in response to IL-12 (Fig 7A and 7B; Pre- transfer). We then sorted transferred cells from naïve CD4+ T cell or Il4gfp+ Th2 cell recipient Rag1–/–mice 2 weeks post-transfer and found that both populations were responsive to IL-12 (Fig 7A and 7B; Post-transfer). Thus, it was possible that IL-12 was promoting IFNγ expression in Th2 cells following P. chabaudi infection. We tested the role of IL-12 by transferring naïve or Il4gfp+ Th2 cells to Rag1–/–mice and blocking IL-12 prior to and after P. chabaudi infection (Fig 7C). Blocking IL-12 reduced expression of Ifngyfp in naïve T cells (reduced from 78.9% to 52.61%); however, IL-12 blockade did not substantially alter the frequency of Ifngyfp+ cells derived from Th2 cells. Instead, IL-12 blockade maintained expression of Il4gfp+ in the Th2 population, with significantly larger Il4gfp+ and Il4gfp+Ifngyfp+ populations (Fig 7D–7F). These data indicate that in this system IL-12 down-regulated Il4gfp expression, but was not required for IFNγ from Th2 cells. Furthermore, neutralization of IL-12 did not impact parasitemia (Fig 7G).

Bottom Line: Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines.Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells.In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection.

View Article: PubMed Central - PubMed

Affiliation: Division of Molecular Immunology, The Francis Crick Institute, London, United Kingdom.

ABSTRACT
Parasitic helminths establish chronic infections in mammalian hosts. Helminth/Plasmodium co-infections occur frequently in endemic areas. However, it is unclear whether Plasmodium infections compromise anti-helminth immunity, contributing to the chronicity of infection. Immunity to Plasmodium or helminths requires divergent CD4+ T cell-driven responses, dominated by IFNγ or IL-4, respectively. Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines. Whether such plasticity occurs during co-infection is unclear. In this study, we observed reduced anti-helminth Th2 cell responses and compromised anti-helminth immunity during Heligmosomoides polygyrus and Plasmodium chabaudi co-infection. Using newly established triple cytokine reporter mice (Il4gfpIfngyfpIl17aFP635), we demonstrated that Il4gfp+ Th2 cells purified from in vitro cultures or isolated ex vivo from helminth-infected mice up-regulated IFNγ following adoptive transfer into Rag1-/- mice infected with P. chabaudi. Functionally, Th2 cells that up-regulated IFNγ were transcriptionally re-wired and protected recipient mice from high parasitemia. Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells. Finally, blockade of IL-12 and IFNγ during co-infection partially preserved anti-helminth Th2 responses. In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection. Consequently, co-infection with Plasmodium spp. may contribute to the chronicity of helminth infection by reducing anti-helminth Th2 cells and converting them into IFNγ-secreting cells.

No MeSH data available.


Related in: MedlinePlus