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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

TCR stimulation is critical for IFNγ production by Th2 cells.A–D). OTII Rag1–/–Il4gfp or Il4gfp Th2 cells (CD4+TCRβ+Il4gfp+) were transferred to Rag1–/–recipient mice. 14 days later, mice were infected with 105P. chabaudi, and mice were harvested at d8 post-infection. Representative of 2 independent experiments with 5 mice per group. B). Cytokine expression in transferred cells in the spleen (IFNγ by ICS, Il4gfp reporter expression). C). IFNγ protein in serum, measured by ELISA. D). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. E–H). Th2 cells (CD4+TCRβ+Il4gfp+Ifngyfp-Il17aFP635-) were transferred to MHC Class II sufficient or deficient Rag1–/–recipients. Mice were infected with 105P. chabaudi at day 14, and mice were harvested at day 8 post-infection. Representative of 2 independent experiments with 5 mice per group. F). Cytokine reporter expression in transferred cells in the spleen. G). IFNγ protein in serum, measured by ELISA. H). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. * denotes P<0.05.
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ppat.1004994.g005: TCR stimulation is critical for IFNγ production by Th2 cells.A–D). OTII Rag1–/–Il4gfp or Il4gfp Th2 cells (CD4+TCRβ+Il4gfp+) were transferred to Rag1–/–recipient mice. 14 days later, mice were infected with 105P. chabaudi, and mice were harvested at d8 post-infection. Representative of 2 independent experiments with 5 mice per group. B). Cytokine expression in transferred cells in the spleen (IFNγ by ICS, Il4gfp reporter expression). C). IFNγ protein in serum, measured by ELISA. D). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. E–H). Th2 cells (CD4+TCRβ+Il4gfp+Ifngyfp-Il17aFP635-) were transferred to MHC Class II sufficient or deficient Rag1–/–recipients. Mice were infected with 105P. chabaudi at day 14, and mice were harvested at day 8 post-infection. Representative of 2 independent experiments with 5 mice per group. F). Cytokine reporter expression in transferred cells in the spleen. G). IFNγ protein in serum, measured by ELISA. H). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. * denotes P<0.05.

Mentions: Given that Th cells require both TCR stimulation and cytokine-mediated signaling for differentiation, it was conceivable that pre-activated Th2 cells in this system would only require a second cytokine receptor-mediated signal to up-regulate IFNγ, without the need for any additional TCR stimulation. We took two independent approaches to test whether TCR engagement was required for Th2 cells to produce IFNγ. First, we generated and FACS-purified TCR-restricted Th2 cells from OTII Rag1–/–mice crossed with Il4gfp reporter mice. We then transferred these OVA-specific Il4gfp+ Th2 cells into Rag1–/–recipients (devoid of OVA) and infected recipient mice with P. chabaudi (Fig 5A). Unlike polyclonal Il4gfp+ Th2 cells that lost expression of Il4gfp and produced IFNγ, antigen-restricted OTII Il4gfp+ Th2 cells retained expression of Il4gfp and failed to produce IFNγ (Fig 5B). Furthermore, IFNγ was not detectable in the serum of mice that received OVA-specific Il4gfp+ Th2 cells (Fig 5C). Functionally, the failure to produce IFNγ correlated with significantly higher parasitemia, comparable to mice that received no T cells (Fig 5D). These data indicate that TCR signaling was required for the functional conversion of Th2 cells into IFNγ-secreting cells. To verify the requirement of TCR-signaling for conversion, we transferred purified Il4gfp+Ifngyfp–Il17aFP365– Th2 cells into Rag1–/–recipient mice which were also deficient in MHC Class II and therefore unable to present antigens to Il4gfp+ Th2 cells. Recipient mice were infected with P. chabaudi, and transferred cells were analyzed at day 8 post-infection (Fig 5E). As before, Il4gfp+ Th2 cells transferred into MHC Class II-sufficient Rag1–/–recipient mice down-regulated Il4gfp and up-regulated Ifngyfp. However, Il4gfp+ Th2 cells transferred to MHC Class II-deficient Rag1–/–recipient mice remained Il4gfp+, did not express Ifngyfp (Fig 5F) and failed to reduce severe parasitemia (Fig 5H). IFNγ was also undetectable in the serum (Fig 5G). Taken together, these two experimental systems demonstrate that conversion of Th2 cells in this model requires TCR engagement.


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)

TCR stimulation is critical for IFNγ production by Th2 cells.A–D). OTII Rag1–/–Il4gfp or Il4gfp Th2 cells (CD4+TCRβ+Il4gfp+) were transferred to Rag1–/–recipient mice. 14 days later, mice were infected with 105P. chabaudi, and mice were harvested at d8 post-infection. Representative of 2 independent experiments with 5 mice per group. B). Cytokine expression in transferred cells in the spleen (IFNγ by ICS, Il4gfp reporter expression). C). IFNγ protein in serum, measured by ELISA. D). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. E–H). Th2 cells (CD4+TCRβ+Il4gfp+Ifngyfp-Il17aFP635-) were transferred to MHC Class II sufficient or deficient Rag1–/–recipients. Mice were infected with 105P. chabaudi at day 14, and mice were harvested at day 8 post-infection. Representative of 2 independent experiments with 5 mice per group. F). Cytokine reporter expression in transferred cells in the spleen. G). IFNγ protein in serum, measured by ELISA. H). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. * denotes P<0.05.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4493106&req=5

ppat.1004994.g005: TCR stimulation is critical for IFNγ production by Th2 cells.A–D). OTII Rag1–/–Il4gfp or Il4gfp Th2 cells (CD4+TCRβ+Il4gfp+) were transferred to Rag1–/–recipient mice. 14 days later, mice were infected with 105P. chabaudi, and mice were harvested at d8 post-infection. Representative of 2 independent experiments with 5 mice per group. B). Cytokine expression in transferred cells in the spleen (IFNγ by ICS, Il4gfp reporter expression). C). IFNγ protein in serum, measured by ELISA. D). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. E–H). Th2 cells (CD4+TCRβ+Il4gfp+Ifngyfp-Il17aFP635-) were transferred to MHC Class II sufficient or deficient Rag1–/–recipients. Mice were infected with 105P. chabaudi at day 14, and mice were harvested at day 8 post-infection. Representative of 2 independent experiments with 5 mice per group. F). Cytokine reporter expression in transferred cells in the spleen. G). IFNγ protein in serum, measured by ELISA. H). Percent parasitemia, determined by blinded counting of Giemsa-stained blood smears. * denotes P<0.05.
Mentions: Given that Th cells require both TCR stimulation and cytokine-mediated signaling for differentiation, it was conceivable that pre-activated Th2 cells in this system would only require a second cytokine receptor-mediated signal to up-regulate IFNγ, without the need for any additional TCR stimulation. We took two independent approaches to test whether TCR engagement was required for Th2 cells to produce IFNγ. First, we generated and FACS-purified TCR-restricted Th2 cells from OTII Rag1–/–mice crossed with Il4gfp reporter mice. We then transferred these OVA-specific Il4gfp+ Th2 cells into Rag1–/–recipients (devoid of OVA) and infected recipient mice with P. chabaudi (Fig 5A). Unlike polyclonal Il4gfp+ Th2 cells that lost expression of Il4gfp and produced IFNγ, antigen-restricted OTII Il4gfp+ Th2 cells retained expression of Il4gfp and failed to produce IFNγ (Fig 5B). Furthermore, IFNγ was not detectable in the serum of mice that received OVA-specific Il4gfp+ Th2 cells (Fig 5C). Functionally, the failure to produce IFNγ correlated with significantly higher parasitemia, comparable to mice that received no T cells (Fig 5D). These data indicate that TCR signaling was required for the functional conversion of Th2 cells into IFNγ-secreting cells. To verify the requirement of TCR-signaling for conversion, we transferred purified Il4gfp+Ifngyfp–Il17aFP365– Th2 cells into Rag1–/–recipient mice which were also deficient in MHC Class II and therefore unable to present antigens to Il4gfp+ Th2 cells. Recipient mice were infected with P. chabaudi, and transferred cells were analyzed at day 8 post-infection (Fig 5E). As before, Il4gfp+ Th2 cells transferred into MHC Class II-sufficient Rag1–/–recipient mice down-regulated Il4gfp and up-regulated Ifngyfp. However, Il4gfp+ Th2 cells transferred to MHC Class II-deficient Rag1–/–recipient mice remained Il4gfp+, did not express Ifngyfp (Fig 5F) and failed to reduce severe parasitemia (Fig 5H). IFNγ was also undetectable in the serum (Fig 5G). Taken together, these two experimental systems demonstrate that conversion of Th2 cells in this model requires TCR engagement.

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