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Glycans from Fasciola hepatica Modulate the Host Immune Response and TLR-Induced Maturation of Dendritic Cells.

Rodríguez E, Noya V, Cervi L, Chiribao ML, Brossard N, Chiale C, Carmona C, Giacomini C, Freire T - PLoS Negl Trop Dis (2015)

Bottom Line: Our results indicate that glycans from F. hepatica promote the production of IL-4 and IL-10, suppressing IFNγ production.Inhibition assays using carbohydrates suggest that the immune-modulation is mediated, at least in part, by the recognition of a mannose specific-CLR that signals by recruiting the phosphatase Php2.The results presented here contribute to the understanding of the role of parasite glycosylated molecules in the modulation of the host immunity and might be useful in the design of vaccines against fasciolosis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunomodulation and Vaccine Development, Departamento de Inmunobiología, Facultad de Medicina, UdelaR, Montevideo, Uruguay.

ABSTRACT
Helminths express various carbohydrate-containing glycoconjugates on their surface, and they release glycan-rich excretion/secretion products that can be very important in their life cycles, infection and pathology. Recent evidence suggests that parasite glycoconjugates could play a role in the evasion of the immune response, leading to a modified Th2-polarized immune response that favors parasite survival in the host. Nevertheless, there is limited information about the nature or function of glycans produced by the trematode Fasciola hepatica, the causative agent of fasciolosis. In this paper, we investigate whether glycosylated molecules from F. hepatica participate in the modulation of host immunity. We also focus on dendritic cells, since they are an important target of immune-modulation by helminths, affecting their activity or function. Our results indicate that glycans from F. hepatica promote the production of IL-4 and IL-10, suppressing IFNγ production. During infection, this parasite is able to induce a semi-mature phenotype of DCs expressing low levels of MHCII and secrete IL-10. Furthermore, we show that parasite glycoconjugates mediate the modulation of LPS-induced maturation of DCs since their oxidation restores the capacity of LPS-treated DCs to secrete high levels of the pro-inflammatory cytokines IL-6 and IL-12/23p40 and low levels of the anti-inflammatory cytokine IL-10. Inhibition assays using carbohydrates suggest that the immune-modulation is mediated, at least in part, by the recognition of a mannose specific-CLR that signals by recruiting the phosphatase Php2. The results presented here contribute to the understanding of the role of parasite glycosylated molecules in the modulation of the host immunity and might be useful in the design of vaccines against fasciolosis.

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BMDCs pulsed with oxidized parasite lysate induce a decreased production of IL-4 and IL-10 by specific CD4+ T cells.BMDCs were cultured in the presence of 75 μg/mL of FhTE, FhCB (oxidation negative control) or FhmPox (oxidized FhTE) in the presence of LPS (1 μg/ml) overnight at 37°C. Then cell viability was evaluated by incubating with MTT for 4 h and reading absorbance at 570 nm (A). Alternatively, BMDCs were washed twice in complete medium and co-cultured for 3 days at 37°C with total splenocytes (B) or purified CD4+ T cells (C) from infected animals sacrificed after 3 wpi. Culture supernatants were collected and analyzed by ELISA for IL-4, IL-5, IL-10 or IFNγ Results are expressed as the mean of three independent experiments (±SD, indicated by error bars). Asterisks indicate statistically significant differences (**p < 0.01; *p < 0.05) with respect to FhTE/LPS-stimulated DCs.
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pntd.0004234.g005: BMDCs pulsed with oxidized parasite lysate induce a decreased production of IL-4 and IL-10 by specific CD4+ T cells.BMDCs were cultured in the presence of 75 μg/mL of FhTE, FhCB (oxidation negative control) or FhmPox (oxidized FhTE) in the presence of LPS (1 μg/ml) overnight at 37°C. Then cell viability was evaluated by incubating with MTT for 4 h and reading absorbance at 570 nm (A). Alternatively, BMDCs were washed twice in complete medium and co-cultured for 3 days at 37°C with total splenocytes (B) or purified CD4+ T cells (C) from infected animals sacrificed after 3 wpi. Culture supernatants were collected and analyzed by ELISA for IL-4, IL-5, IL-10 or IFNγ Results are expressed as the mean of three independent experiments (±SD, indicated by error bars). Asterisks indicate statistically significant differences (**p < 0.01; *p < 0.05) with respect to FhTE/LPS-stimulated DCs.

Mentions: In order to determine whether parasite glycan structures can also modulate the function of DCs, we evaluated the in vitro activation of splenocytes (Fig 5B) and purified CD4+ T cells (Fig 5C) from infected animals by DCs. To this end, bone marrow derived DCs (BMDCs) were loaded with parasite-derived components (FhTE) or with oxidized total lysate (FhmPox). A control consisting on FhTE subjected to the chemical process in absence of meta-periodate was also included (FhCB). Importantly, the viability of loaded-BMDC was not affected by the treatment with different parasite lysates (Fig 5A). Then, loaded BMDCs were washed and subsequently incubated with splenocytes or purified CD4+ T cells from infected animals. As seen in Fig 5B and 5C, when incubated with FhmPox-loaded BMDCs, splenocytes and purified CD4+ T cells produced lower levels of IL-4 and IL-10 than cells stimulated with FhTE-loaded BMDCs, while IL-5 and IFNγ production remained unchanged. No cytokine production was detected when loaded BMDCs were incubated with splenocytes or purified CD4+ T cells from uninfected animals (naïve) (Fig 5B and 5C). These results strongly suggest that glycoconjugates modulate DC-stimulatory capacity by increasing the production of IL-4 and IL-10 by CD4+ T cells during infection.


Glycans from Fasciola hepatica Modulate the Host Immune Response and TLR-Induced Maturation of Dendritic Cells.

Rodríguez E, Noya V, Cervi L, Chiribao ML, Brossard N, Chiale C, Carmona C, Giacomini C, Freire T - PLoS Negl Trop Dis (2015)

BMDCs pulsed with oxidized parasite lysate induce a decreased production of IL-4 and IL-10 by specific CD4+ T cells.BMDCs were cultured in the presence of 75 μg/mL of FhTE, FhCB (oxidation negative control) or FhmPox (oxidized FhTE) in the presence of LPS (1 μg/ml) overnight at 37°C. Then cell viability was evaluated by incubating with MTT for 4 h and reading absorbance at 570 nm (A). Alternatively, BMDCs were washed twice in complete medium and co-cultured for 3 days at 37°C with total splenocytes (B) or purified CD4+ T cells (C) from infected animals sacrificed after 3 wpi. Culture supernatants were collected and analyzed by ELISA for IL-4, IL-5, IL-10 or IFNγ Results are expressed as the mean of three independent experiments (±SD, indicated by error bars). Asterisks indicate statistically significant differences (**p < 0.01; *p < 0.05) with respect to FhTE/LPS-stimulated DCs.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4697847&req=5

pntd.0004234.g005: BMDCs pulsed with oxidized parasite lysate induce a decreased production of IL-4 and IL-10 by specific CD4+ T cells.BMDCs were cultured in the presence of 75 μg/mL of FhTE, FhCB (oxidation negative control) or FhmPox (oxidized FhTE) in the presence of LPS (1 μg/ml) overnight at 37°C. Then cell viability was evaluated by incubating with MTT for 4 h and reading absorbance at 570 nm (A). Alternatively, BMDCs were washed twice in complete medium and co-cultured for 3 days at 37°C with total splenocytes (B) or purified CD4+ T cells (C) from infected animals sacrificed after 3 wpi. Culture supernatants were collected and analyzed by ELISA for IL-4, IL-5, IL-10 or IFNγ Results are expressed as the mean of three independent experiments (±SD, indicated by error bars). Asterisks indicate statistically significant differences (**p < 0.01; *p < 0.05) with respect to FhTE/LPS-stimulated DCs.
Mentions: In order to determine whether parasite glycan structures can also modulate the function of DCs, we evaluated the in vitro activation of splenocytes (Fig 5B) and purified CD4+ T cells (Fig 5C) from infected animals by DCs. To this end, bone marrow derived DCs (BMDCs) were loaded with parasite-derived components (FhTE) or with oxidized total lysate (FhmPox). A control consisting on FhTE subjected to the chemical process in absence of meta-periodate was also included (FhCB). Importantly, the viability of loaded-BMDC was not affected by the treatment with different parasite lysates (Fig 5A). Then, loaded BMDCs were washed and subsequently incubated with splenocytes or purified CD4+ T cells from infected animals. As seen in Fig 5B and 5C, when incubated with FhmPox-loaded BMDCs, splenocytes and purified CD4+ T cells produced lower levels of IL-4 and IL-10 than cells stimulated with FhTE-loaded BMDCs, while IL-5 and IFNγ production remained unchanged. No cytokine production was detected when loaded BMDCs were incubated with splenocytes or purified CD4+ T cells from uninfected animals (naïve) (Fig 5B and 5C). These results strongly suggest that glycoconjugates modulate DC-stimulatory capacity by increasing the production of IL-4 and IL-10 by CD4+ T cells during infection.

Bottom Line: Our results indicate that glycans from F. hepatica promote the production of IL-4 and IL-10, suppressing IFNγ production.Inhibition assays using carbohydrates suggest that the immune-modulation is mediated, at least in part, by the recognition of a mannose specific-CLR that signals by recruiting the phosphatase Php2.The results presented here contribute to the understanding of the role of parasite glycosylated molecules in the modulation of the host immunity and might be useful in the design of vaccines against fasciolosis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunomodulation and Vaccine Development, Departamento de Inmunobiología, Facultad de Medicina, UdelaR, Montevideo, Uruguay.

ABSTRACT
Helminths express various carbohydrate-containing glycoconjugates on their surface, and they release glycan-rich excretion/secretion products that can be very important in their life cycles, infection and pathology. Recent evidence suggests that parasite glycoconjugates could play a role in the evasion of the immune response, leading to a modified Th2-polarized immune response that favors parasite survival in the host. Nevertheless, there is limited information about the nature or function of glycans produced by the trematode Fasciola hepatica, the causative agent of fasciolosis. In this paper, we investigate whether glycosylated molecules from F. hepatica participate in the modulation of host immunity. We also focus on dendritic cells, since they are an important target of immune-modulation by helminths, affecting their activity or function. Our results indicate that glycans from F. hepatica promote the production of IL-4 and IL-10, suppressing IFNγ production. During infection, this parasite is able to induce a semi-mature phenotype of DCs expressing low levels of MHCII and secrete IL-10. Furthermore, we show that parasite glycoconjugates mediate the modulation of LPS-induced maturation of DCs since their oxidation restores the capacity of LPS-treated DCs to secrete high levels of the pro-inflammatory cytokines IL-6 and IL-12/23p40 and low levels of the anti-inflammatory cytokine IL-10. Inhibition assays using carbohydrates suggest that the immune-modulation is mediated, at least in part, by the recognition of a mannose specific-CLR that signals by recruiting the phosphatase Php2. The results presented here contribute to the understanding of the role of parasite glycosylated molecules in the modulation of the host immunity and might be useful in the design of vaccines against fasciolosis.

Show MeSH
Related in: MedlinePlus