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Type I IFN controls chikungunya virus via its action on nonhematopoietic cells.

Schilte C, Couderc T, Chretien F, Sourisseau M, Gangneux N, Guivel-Benhassine F, Kraxner A, Tschopp J, Higgs S, Michault A, Arenzana-Seisdedos F, Colonna M, Peduto L, Schwartz O, Lecuit M, Albert ML - J. Exp. Med. (2010)

Bottom Line: Based on human studies and mouse experimentation, we show that CHIKV does not directly stimulate type I IFN production in immune cells.Moreover, we demonstrate that IFN-alpha/beta receptor (IFNAR) expression is required in the periphery but not on immune cells, as IFNAR(-/-)-->WT bone marrow chimeras are capable of clearing the infection, whereas WT-->IFNAR(-/-) chimeras succumb.This study defines an essential role for type I IFN, produced via cooperation between multiple host sensors and acting directly on nonhematopoietic cells, in the control of CHIKV.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Immunology, Unité Immunobiologie des Cellules Dendritiques, Institut Pasteur, 75724 Paris, Cedex 15, France.

ABSTRACT
Chikungunya virus (CHIKV) is the causative agent of an outbreak that began in La Réunion in 2005 and remains a major public health concern in India, Southeast Asia, and southern Europe. CHIKV is transmitted to humans by mosquitoes and the associated disease is characterized by fever, myalgia, arthralgia, and rash. As viral load in infected patients declines before the appearance of neutralizing antibodies, we studied the role of type I interferon (IFN) in CHIKV pathogenesis. Based on human studies and mouse experimentation, we show that CHIKV does not directly stimulate type I IFN production in immune cells. Instead, infected nonhematopoietic cells sense viral RNA in a Cardif-dependent manner and participate in the control of infection through their production of type I IFNs. Although the Cardif signaling pathway contributes to the immune response, we also find evidence for a MyD88-dependent sensor that is critical for preventing viral dissemination. Moreover, we demonstrate that IFN-alpha/beta receptor (IFNAR) expression is required in the periphery but not on immune cells, as IFNAR(-/-)-->WT bone marrow chimeras are capable of clearing the infection, whereas WT-->IFNAR(-/-) chimeras succumb. This study defines an essential role for type I IFN, produced via cooperation between multiple host sensors and acting directly on nonhematopoietic cells, in the control of CHIKV.

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CHIKV induces IFN-α/β in vivo in humans but fails to stimulate production in hematopoietic cells. (A) Patient sera samples were obtained from consenting CHIKV-infected adults (age = 16–86 yr; n = 25) and age-matched controls (age range = 16–89 yr; n = 17). IFN-α was monitored by luminex and plotted as a function of viral load, measured by quantitative PCR. Mean IFN-α serum concentration in the control population was 179 pg/ml, indicated by the dotted line. The solid line represents the linear regression between viral load and IFN-α in patients. (B) Monocyte-derived DCs were generated from healthy donors, and 105 immature DCs (iDCs) or mature DCs (mDCs) were exposed to CHIKV. In parallel, 3 × 104 freshly isolated pDCs or 106 PBMCs were cultured with CHIKV. In the experiment shown, 106 PFU/ml was used and cells were incubated for 40 h. Culture supernatants were analyzed for IFN-α/β production by a reporter assay involving an IFNAR-expressing cell line, HL-116, stably transfected with a plasmid encoding an IFN-inducible luciferase gene (limit of detection, 5 IFN U/ml). 50 HAU influenza A/PR8 or 50 µg/ml poly I:C were used as a positive control. Results were identical for three different donors. Similar results were found in monocyte-derived macrophages (not depicted). (C and D) Human foreskin fibroblasts (black) or MRC-5 cell lines (white) were infected at increasing MOI and cultured for 48 h. Cells were harvested and intracellular staining was performed using an anti-CHIKV mAb and analyzed by FACS (C). In parallel, culture supernatant was analyzed for IFN-β by Elisa (limit of detection, 20 pg/ml; D). Error bars indicate SD. Data is representative of five experiments.
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fig1: CHIKV induces IFN-α/β in vivo in humans but fails to stimulate production in hematopoietic cells. (A) Patient sera samples were obtained from consenting CHIKV-infected adults (age = 16–86 yr; n = 25) and age-matched controls (age range = 16–89 yr; n = 17). IFN-α was monitored by luminex and plotted as a function of viral load, measured by quantitative PCR. Mean IFN-α serum concentration in the control population was 179 pg/ml, indicated by the dotted line. The solid line represents the linear regression between viral load and IFN-α in patients. (B) Monocyte-derived DCs were generated from healthy donors, and 105 immature DCs (iDCs) or mature DCs (mDCs) were exposed to CHIKV. In parallel, 3 × 104 freshly isolated pDCs or 106 PBMCs were cultured with CHIKV. In the experiment shown, 106 PFU/ml was used and cells were incubated for 40 h. Culture supernatants were analyzed for IFN-α/β production by a reporter assay involving an IFNAR-expressing cell line, HL-116, stably transfected with a plasmid encoding an IFN-inducible luciferase gene (limit of detection, 5 IFN U/ml). 50 HAU influenza A/PR8 or 50 µg/ml poly I:C were used as a positive control. Results were identical for three different donors. Similar results were found in monocyte-derived macrophages (not depicted). (C and D) Human foreskin fibroblasts (black) or MRC-5 cell lines (white) were infected at increasing MOI and cultured for 48 h. Cells were harvested and intracellular staining was performed using an anti-CHIKV mAb and analyzed by FACS (C). In parallel, culture supernatant was analyzed for IFN-β by Elisa (limit of detection, 20 pg/ml; D). Error bars indicate SD. Data is representative of five experiments.

Mentions: To establish a role for the induction of type I IFNs by CHIKV infection, we analyzed serum from a patient cohort recruited during the 2005–2006 outbreak in La Réunion. Indeed, IFN-α was detected at high levels in the serum of infected individuals with its concentration correlating with viral load (Fig. 1 A). It is of note that plasma concentrations of IFN-γ in infected individuals were not statistically different from controls (unpublished data). We thus investigated the mechanisms, accounting for the production of type I IFNs during infection. Primary isolates of CHIKV were obtained and their genome sequence was determined (Schuffenecker et al., 2006). A representative isolate, CHIKV-21, is presented in this study. To avoid laboratory adaptation, viruses were amplified only twice in C6/36 mosquito cells and titrated by plaque assay on BHK cells.


Type I IFN controls chikungunya virus via its action on nonhematopoietic cells.

Schilte C, Couderc T, Chretien F, Sourisseau M, Gangneux N, Guivel-Benhassine F, Kraxner A, Tschopp J, Higgs S, Michault A, Arenzana-Seisdedos F, Colonna M, Peduto L, Schwartz O, Lecuit M, Albert ML - J. Exp. Med. (2010)

CHIKV induces IFN-α/β in vivo in humans but fails to stimulate production in hematopoietic cells. (A) Patient sera samples were obtained from consenting CHIKV-infected adults (age = 16–86 yr; n = 25) and age-matched controls (age range = 16–89 yr; n = 17). IFN-α was monitored by luminex and plotted as a function of viral load, measured by quantitative PCR. Mean IFN-α serum concentration in the control population was 179 pg/ml, indicated by the dotted line. The solid line represents the linear regression between viral load and IFN-α in patients. (B) Monocyte-derived DCs were generated from healthy donors, and 105 immature DCs (iDCs) or mature DCs (mDCs) were exposed to CHIKV. In parallel, 3 × 104 freshly isolated pDCs or 106 PBMCs were cultured with CHIKV. In the experiment shown, 106 PFU/ml was used and cells were incubated for 40 h. Culture supernatants were analyzed for IFN-α/β production by a reporter assay involving an IFNAR-expressing cell line, HL-116, stably transfected with a plasmid encoding an IFN-inducible luciferase gene (limit of detection, 5 IFN U/ml). 50 HAU influenza A/PR8 or 50 µg/ml poly I:C were used as a positive control. Results were identical for three different donors. Similar results were found in monocyte-derived macrophages (not depicted). (C and D) Human foreskin fibroblasts (black) or MRC-5 cell lines (white) were infected at increasing MOI and cultured for 48 h. Cells were harvested and intracellular staining was performed using an anti-CHIKV mAb and analyzed by FACS (C). In parallel, culture supernatant was analyzed for IFN-β by Elisa (limit of detection, 20 pg/ml; D). Error bars indicate SD. Data is representative of five experiments.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2822618&req=5

fig1: CHIKV induces IFN-α/β in vivo in humans but fails to stimulate production in hematopoietic cells. (A) Patient sera samples were obtained from consenting CHIKV-infected adults (age = 16–86 yr; n = 25) and age-matched controls (age range = 16–89 yr; n = 17). IFN-α was monitored by luminex and plotted as a function of viral load, measured by quantitative PCR. Mean IFN-α serum concentration in the control population was 179 pg/ml, indicated by the dotted line. The solid line represents the linear regression between viral load and IFN-α in patients. (B) Monocyte-derived DCs were generated from healthy donors, and 105 immature DCs (iDCs) or mature DCs (mDCs) were exposed to CHIKV. In parallel, 3 × 104 freshly isolated pDCs or 106 PBMCs were cultured with CHIKV. In the experiment shown, 106 PFU/ml was used and cells were incubated for 40 h. Culture supernatants were analyzed for IFN-α/β production by a reporter assay involving an IFNAR-expressing cell line, HL-116, stably transfected with a plasmid encoding an IFN-inducible luciferase gene (limit of detection, 5 IFN U/ml). 50 HAU influenza A/PR8 or 50 µg/ml poly I:C were used as a positive control. Results were identical for three different donors. Similar results were found in monocyte-derived macrophages (not depicted). (C and D) Human foreskin fibroblasts (black) or MRC-5 cell lines (white) were infected at increasing MOI and cultured for 48 h. Cells were harvested and intracellular staining was performed using an anti-CHIKV mAb and analyzed by FACS (C). In parallel, culture supernatant was analyzed for IFN-β by Elisa (limit of detection, 20 pg/ml; D). Error bars indicate SD. Data is representative of five experiments.
Mentions: To establish a role for the induction of type I IFNs by CHIKV infection, we analyzed serum from a patient cohort recruited during the 2005–2006 outbreak in La Réunion. Indeed, IFN-α was detected at high levels in the serum of infected individuals with its concentration correlating with viral load (Fig. 1 A). It is of note that plasma concentrations of IFN-γ in infected individuals were not statistically different from controls (unpublished data). We thus investigated the mechanisms, accounting for the production of type I IFNs during infection. Primary isolates of CHIKV were obtained and their genome sequence was determined (Schuffenecker et al., 2006). A representative isolate, CHIKV-21, is presented in this study. To avoid laboratory adaptation, viruses were amplified only twice in C6/36 mosquito cells and titrated by plaque assay on BHK cells.

Bottom Line: Based on human studies and mouse experimentation, we show that CHIKV does not directly stimulate type I IFN production in immune cells.Moreover, we demonstrate that IFN-alpha/beta receptor (IFNAR) expression is required in the periphery but not on immune cells, as IFNAR(-/-)-->WT bone marrow chimeras are capable of clearing the infection, whereas WT-->IFNAR(-/-) chimeras succumb.This study defines an essential role for type I IFN, produced via cooperation between multiple host sensors and acting directly on nonhematopoietic cells, in the control of CHIKV.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Immunology, Unité Immunobiologie des Cellules Dendritiques, Institut Pasteur, 75724 Paris, Cedex 15, France.

ABSTRACT
Chikungunya virus (CHIKV) is the causative agent of an outbreak that began in La Réunion in 2005 and remains a major public health concern in India, Southeast Asia, and southern Europe. CHIKV is transmitted to humans by mosquitoes and the associated disease is characterized by fever, myalgia, arthralgia, and rash. As viral load in infected patients declines before the appearance of neutralizing antibodies, we studied the role of type I interferon (IFN) in CHIKV pathogenesis. Based on human studies and mouse experimentation, we show that CHIKV does not directly stimulate type I IFN production in immune cells. Instead, infected nonhematopoietic cells sense viral RNA in a Cardif-dependent manner and participate in the control of infection through their production of type I IFNs. Although the Cardif signaling pathway contributes to the immune response, we also find evidence for a MyD88-dependent sensor that is critical for preventing viral dissemination. Moreover, we demonstrate that IFN-alpha/beta receptor (IFNAR) expression is required in the periphery but not on immune cells, as IFNAR(-/-)-->WT bone marrow chimeras are capable of clearing the infection, whereas WT-->IFNAR(-/-) chimeras succumb. This study defines an essential role for type I IFN, produced via cooperation between multiple host sensors and acting directly on nonhematopoietic cells, in the control of CHIKV.

Show MeSH
Related in: MedlinePlus