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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

In vitro Th2 cells produce IFNγ and protect Rag1–/–mice during Plasmodium infection.A). Experimental set-up: 2-week in vitro polarized Th2 cells were FACS sorted as CD4+Il4gfp+Ifngyfp–Il17aFP635– and transferred i.v. to Rag1–/–mice. As a control, a group of Rag1–/–mice received naïve CD4+ T cells. A second control group received no T cells. Recipient mice were infected with 105P. chabaudi i.p. on day 14 post-transfer and harvested at day 8 post-infection. B). Percent and total number of CD4+Il4gfp+ and Ifngyfp+ cells in the spleen, as determined by FACS. C). Serum IFNγ levels determined by ELISA. D). Percent parasitemia was determined by blinded counting of Giemsa-stained blood smears. E and F). Hemoglobin and eHred blood cell counts were measured in peripheral blood by Vetscan. Data is representative of at least 3 independent experiments, with 3–5 mice per group. G). Converted CD4+TCRβ+Ifngyfp+Il4gfp–Il17aFP635– cells were sorted from pooled spleens of 3 recipient Rag1–/–mice at day 8 post-P. chabaudi infection. H). Sorted Ifngyfp+ cells were cultured in vitro in Th2 conditions for 5 days. ELISAs for IFNγ (H), IL-5 and IL-13 (I) were run on cell supernatants. Error bars represent technical replicates. Data are representative of 3 independent experiments. * denotes P<0.05.
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ppat.1004994.g002: In vitro Th2 cells produce IFNγ and protect Rag1–/–mice during Plasmodium infection.A). Experimental set-up: 2-week in vitro polarized Th2 cells were FACS sorted as CD4+Il4gfp+Ifngyfp–Il17aFP635– and transferred i.v. to Rag1–/–mice. As a control, a group of Rag1–/–mice received naïve CD4+ T cells. A second control group received no T cells. Recipient mice were infected with 105P. chabaudi i.p. on day 14 post-transfer and harvested at day 8 post-infection. B). Percent and total number of CD4+Il4gfp+ and Ifngyfp+ cells in the spleen, as determined by FACS. C). Serum IFNγ levels determined by ELISA. D). Percent parasitemia was determined by blinded counting of Giemsa-stained blood smears. E and F). Hemoglobin and eHred blood cell counts were measured in peripheral blood by Vetscan. Data is representative of at least 3 independent experiments, with 3–5 mice per group. G). Converted CD4+TCRβ+Ifngyfp+Il4gfp–Il17aFP635– cells were sorted from pooled spleens of 3 recipient Rag1–/–mice at day 8 post-P. chabaudi infection. H). Sorted Ifngyfp+ cells were cultured in vitro in Th2 conditions for 5 days. ELISAs for IFNγ (H), IL-5 and IL-13 (I) were run on cell supernatants. Error bars represent technical replicates. Data are representative of 3 independent experiments. * denotes P<0.05.

Mentions: It has become clear in recent years that lineage-committed CD4+ T cells retain a degree of plasticity, with the ability to convert between phenotypes [30]. Plasmodium infection elicits a polyclonal expansion of lymphocytes and IFNγ-secreting T cells [21,22]. We therefore hypothesized that the loss of Il4gfp+ Th2 cells in the mesenteric lymph nodes and the increase in Ifngyfp+ cells in the spleen during H. polygyrus and P. chabaudi co-infection was due to conversion of Th2 cells to an IFNγ-producing Th1-like phenotype. To test whether Th2 cells could produce IFNγ during P. chabaudi infection, we FACS-purified CD4+TCRβ+Il4gfp+Ifngyfp–Il17aFP365– Th2 cells from 2-week in vitro cultures (S1 Fig), adoptively transferred them into Rag1–/–mice and infected the recipient mice with P. chabaudi. Cytokine expression in the transferred cells was analyzed in the spleen at day 8 post-infection (Fig 2A). Transferred Th2 cells (Il4gfp+Ifngyfp–Il17aFP365–) almost completely lost expression of Il4gfp and, comparable to naïve T cells, expanded with approximately 80% of cells expressing Ifngyfp (Fig 2B). Il17aFP635+ cells were barely detectable (<1%) following Plasmodium infection, in line with previous data [21,22,40]. IFNγ protein was also detectable in the serum of mice that received either naive CD4+ T cells or purified Th2 cells, but not in P. chabaudi-infected Rag1–/–mice that received no T cells, indicating that serum IFNγ was T cell-dependent (Fig 2C). Thin blood smears from recipient mice identified that following infection of Rag1–/–mice, very high parasitemia is observed (Fig 2D). The adoptive transfer of naïve T cells to Rag1–/–mice significantly reduced the high parasitemia, confirming an important T cell-dependent role in the control of high parasitemia during acute infection. This system permitted us to test whether Th2 cells, which had converted into IFNγ+ cells, could also control high parasitemia following acute infection. Indeed, adoptive transfer of Th2 cells also significantly reduced parasitemia (Fig 2D), suggesting a functional loss of hemoglobin and severe anemia were also prevented in Rag1–/–mice given Th2 cells (Fig 2E and 2F). Although Th2 cells up-regulated IFNγ in uninfected recipient Rag1–/–mice, significantly greater expansion of these converted cells occurred in P. chabaudi infected recipient mice (S3 Fig). These data demonstrate that purified Il4-expressing Th2 cells were capable of producing IFNγ and could protect mice during acute P. chabaudi infection, similar to naive CD4+ T cells. Finally, to determine whether Th2 cells had the capacity to produce non-lineage cytokines in another model system, we infected Rag1–/–recipient mice with Candida albicans (S4 Fig). At day 6 post C. albicans infection, transferred Il4gfp+ Th2 cells had lost Il4 expression and up-regulated IFNγ, similar to P. chabaudi infection. Interestingly, transferred Th2 cells did not up-regulate IL-17a, unlike naïve controls (S4 Fig).


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)

In vitro Th2 cells produce IFNγ and protect Rag1–/–mice during Plasmodium infection.A). Experimental set-up: 2-week in vitro polarized Th2 cells were FACS sorted as CD4+Il4gfp+Ifngyfp–Il17aFP635– and transferred i.v. to Rag1–/–mice. As a control, a group of Rag1–/–mice received naïve CD4+ T cells. A second control group received no T cells. Recipient mice were infected with 105P. chabaudi i.p. on day 14 post-transfer and harvested at day 8 post-infection. B). Percent and total number of CD4+Il4gfp+ and Ifngyfp+ cells in the spleen, as determined by FACS. C). Serum IFNγ levels determined by ELISA. D). Percent parasitemia was determined by blinded counting of Giemsa-stained blood smears. E and F). Hemoglobin and eHred blood cell counts were measured in peripheral blood by Vetscan. Data is representative of at least 3 independent experiments, with 3–5 mice per group. G). Converted CD4+TCRβ+Ifngyfp+Il4gfp–Il17aFP635– cells were sorted from pooled spleens of 3 recipient Rag1–/–mice at day 8 post-P. chabaudi infection. H). Sorted Ifngyfp+ cells were cultured in vitro in Th2 conditions for 5 days. ELISAs for IFNγ (H), IL-5 and IL-13 (I) were run on cell supernatants. Error bars represent technical replicates. Data are representative of 3 independent experiments. * denotes P<0.05.
© Copyright Policy
Related In: Results  -  Collection

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

ppat.1004994.g002: In vitro Th2 cells produce IFNγ and protect Rag1–/–mice during Plasmodium infection.A). Experimental set-up: 2-week in vitro polarized Th2 cells were FACS sorted as CD4+Il4gfp+Ifngyfp–Il17aFP635– and transferred i.v. to Rag1–/–mice. As a control, a group of Rag1–/–mice received naïve CD4+ T cells. A second control group received no T cells. Recipient mice were infected with 105P. chabaudi i.p. on day 14 post-transfer and harvested at day 8 post-infection. B). Percent and total number of CD4+Il4gfp+ and Ifngyfp+ cells in the spleen, as determined by FACS. C). Serum IFNγ levels determined by ELISA. D). Percent parasitemia was determined by blinded counting of Giemsa-stained blood smears. E and F). Hemoglobin and eHred blood cell counts were measured in peripheral blood by Vetscan. Data is representative of at least 3 independent experiments, with 3–5 mice per group. G). Converted CD4+TCRβ+Ifngyfp+Il4gfp–Il17aFP635– cells were sorted from pooled spleens of 3 recipient Rag1–/–mice at day 8 post-P. chabaudi infection. H). Sorted Ifngyfp+ cells were cultured in vitro in Th2 conditions for 5 days. ELISAs for IFNγ (H), IL-5 and IL-13 (I) were run on cell supernatants. Error bars represent technical replicates. Data are representative of 3 independent experiments. * denotes P<0.05.
Mentions: It has become clear in recent years that lineage-committed CD4+ T cells retain a degree of plasticity, with the ability to convert between phenotypes [30]. Plasmodium infection elicits a polyclonal expansion of lymphocytes and IFNγ-secreting T cells [21,22]. We therefore hypothesized that the loss of Il4gfp+ Th2 cells in the mesenteric lymph nodes and the increase in Ifngyfp+ cells in the spleen during H. polygyrus and P. chabaudi co-infection was due to conversion of Th2 cells to an IFNγ-producing Th1-like phenotype. To test whether Th2 cells could produce IFNγ during P. chabaudi infection, we FACS-purified CD4+TCRβ+Il4gfp+Ifngyfp–Il17aFP365– Th2 cells from 2-week in vitro cultures (S1 Fig), adoptively transferred them into Rag1–/–mice and infected the recipient mice with P. chabaudi. Cytokine expression in the transferred cells was analyzed in the spleen at day 8 post-infection (Fig 2A). Transferred Th2 cells (Il4gfp+Ifngyfp–Il17aFP365–) almost completely lost expression of Il4gfp and, comparable to naïve T cells, expanded with approximately 80% of cells expressing Ifngyfp (Fig 2B). Il17aFP635+ cells were barely detectable (<1%) following Plasmodium infection, in line with previous data [21,22,40]. IFNγ protein was also detectable in the serum of mice that received either naive CD4+ T cells or purified Th2 cells, but not in P. chabaudi-infected Rag1–/–mice that received no T cells, indicating that serum IFNγ was T cell-dependent (Fig 2C). Thin blood smears from recipient mice identified that following infection of Rag1–/–mice, very high parasitemia is observed (Fig 2D). The adoptive transfer of naïve T cells to Rag1–/–mice significantly reduced the high parasitemia, confirming an important T cell-dependent role in the control of high parasitemia during acute infection. This system permitted us to test whether Th2 cells, which had converted into IFNγ+ cells, could also control high parasitemia following acute infection. Indeed, adoptive transfer of Th2 cells also significantly reduced parasitemia (Fig 2D), suggesting a functional loss of hemoglobin and severe anemia were also prevented in Rag1–/–mice given Th2 cells (Fig 2E and 2F). Although Th2 cells up-regulated IFNγ in uninfected recipient Rag1–/–mice, significantly greater expansion of these converted cells occurred in P. chabaudi infected recipient mice (S3 Fig). These data demonstrate that purified Il4-expressing Th2 cells were capable of producing IFNγ and could protect mice during acute P. chabaudi infection, similar to naive CD4+ T cells. Finally, to determine whether Th2 cells had the capacity to produce non-lineage cytokines in another model system, we infected Rag1–/–recipient mice with Candida albicans (S4 Fig). At day 6 post C. albicans infection, transferred Il4gfp+ Th2 cells had lost Il4 expression and up-regulated IFNγ, similar to P. chabaudi infection. Interestingly, transferred Th2 cells did not up-regulate IL-17a, unlike naïve controls (S4 Fig).

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