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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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F. hepatica infection promotes the recruitment of MHClow IL-10+ DCs both at the peritoneal cavity and spleen.Mice (n = 5 per group) were orally infected with 10 metacercariae in PBS (infected mice). PBS alone served as a control (non-infected mice). Mice were sacrificed one, two and three weeks after the infection and spleens and PECs were removed. Splenocyte (A) and PEC (B) suspensions were counted and the presence of CD11chi cells was analyzed by flow cytometry by staining cells with specific antibodies. CD11chi cells were selected after excluding CD3+ followed by exclusion of F4/80+ cells (C). Splenocytes (D) and PECs (E) were also incubated with anti-MCHII, permeabilized, and intracellularly stained with anti-IL-10 and IL-12/23p40 antibodies for 30 min at 4°C. Cells were analyzed on a flow cytometer. Results are expressed as the mean of three independent experiments (±SD, indicated by error bars). Asterisks indicate statistically significant differences (*p < 0.01) with respect to cells from non-infected animals.
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pntd.0004234.g004: F. hepatica infection promotes the recruitment of MHClow IL-10+ DCs both at the peritoneal cavity and spleen.Mice (n = 5 per group) were orally infected with 10 metacercariae in PBS (infected mice). PBS alone served as a control (non-infected mice). Mice were sacrificed one, two and three weeks after the infection and spleens and PECs were removed. Splenocyte (A) and PEC (B) suspensions were counted and the presence of CD11chi cells was analyzed by flow cytometry by staining cells with specific antibodies. CD11chi cells were selected after excluding CD3+ followed by exclusion of F4/80+ cells (C). Splenocytes (D) and PECs (E) were also incubated with anti-MCHII, permeabilized, and intracellularly stained with anti-IL-10 and IL-12/23p40 antibodies for 30 min at 4°C. Cells were analyzed on a flow cytometer. Results are expressed as the mean of three independent experiments (±SD, indicated by error bars). Asterisks indicate statistically significant differences (*p < 0.01) with respect to cells from non-infected animals.

Mentions: Evidence demonstrating that F. hepatica components can modulate DC-maturation and function in vitro has been previously reported [5–6, 10, 28]. Also, the phenotype of DCs has been evaluated suggesting that the parasite immune-modulates DCs upon infection [13]. Nevertheless, an exhaustive study of DC immune-modulation by the parasite has not been carried out. Thus, in order to deeply evaluate their role in the host immune-modulation by F. hepatica, we sought to evaluate DCs in vivo both in the spleen and in the peritoneum of infected animals. Upon infection, we observed a marked recruitment of cells in the spleen and in the peritoneal cavity of infected animals, which increased with time of infection (Fig 4A and 4B, respectively). Among these cells, DCs (defined as CD11chi F4/80- cells) were recruited both at the spleen and the peritoneum since the first wpi, and their number augmented with the course of infection (Fig 4A and 4B). In spite of the fact that all DCs were MHC class II positive, they presented remarkable decreased levels of MHCII expression (Fig 4C–4E). Indeed, splenic DCs presented around 50% reduction of MHCII expression since the first wpi together with lower levels of CD40 on their surface (S1B Fig). MHC class II- or CD40-decreased expression on DC surface was not modified when infecting animals with higher parasite dose (S1B Fig). Moreover, from the second wpi, an increase of IL-10 secreting splenic DCs was evidenced (Figs 4D and S2). Strikingly, IL-12+ DCs also augmented in the spleen (Fig 4D). DCs recruited into the peritoneum also reduced the expression of MHC class II (Fig 4E) while the expression of CD80 and CD86 was increased (S1C Fig). There was also an increase of IL-10 secreting DCs in the peritoneal cavity, while IL-12 secreting DCs remained very low in the peritoneum (Figs 4E and S2).


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)

F. hepatica infection promotes the recruitment of MHClow IL-10+ DCs both at the peritoneal cavity and spleen.Mice (n = 5 per group) were orally infected with 10 metacercariae in PBS (infected mice). PBS alone served as a control (non-infected mice). Mice were sacrificed one, two and three weeks after the infection and spleens and PECs were removed. Splenocyte (A) and PEC (B) suspensions were counted and the presence of CD11chi cells was analyzed by flow cytometry by staining cells with specific antibodies. CD11chi cells were selected after excluding CD3+ followed by exclusion of F4/80+ cells (C). Splenocytes (D) and PECs (E) were also incubated with anti-MCHII, permeabilized, and intracellularly stained with anti-IL-10 and IL-12/23p40 antibodies for 30 min at 4°C. Cells were analyzed on a flow cytometer. Results are expressed as the mean of three independent experiments (±SD, indicated by error bars). Asterisks indicate statistically significant differences (*p < 0.01) with respect to cells from non-infected animals.
© Copyright Policy
Related In: Results  -  Collection

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

pntd.0004234.g004: F. hepatica infection promotes the recruitment of MHClow IL-10+ DCs both at the peritoneal cavity and spleen.Mice (n = 5 per group) were orally infected with 10 metacercariae in PBS (infected mice). PBS alone served as a control (non-infected mice). Mice were sacrificed one, two and three weeks after the infection and spleens and PECs were removed. Splenocyte (A) and PEC (B) suspensions were counted and the presence of CD11chi cells was analyzed by flow cytometry by staining cells with specific antibodies. CD11chi cells were selected after excluding CD3+ followed by exclusion of F4/80+ cells (C). Splenocytes (D) and PECs (E) were also incubated with anti-MCHII, permeabilized, and intracellularly stained with anti-IL-10 and IL-12/23p40 antibodies for 30 min at 4°C. Cells were analyzed on a flow cytometer. Results are expressed as the mean of three independent experiments (±SD, indicated by error bars). Asterisks indicate statistically significant differences (*p < 0.01) with respect to cells from non-infected animals.
Mentions: Evidence demonstrating that F. hepatica components can modulate DC-maturation and function in vitro has been previously reported [5–6, 10, 28]. Also, the phenotype of DCs has been evaluated suggesting that the parasite immune-modulates DCs upon infection [13]. Nevertheless, an exhaustive study of DC immune-modulation by the parasite has not been carried out. Thus, in order to deeply evaluate their role in the host immune-modulation by F. hepatica, we sought to evaluate DCs in vivo both in the spleen and in the peritoneum of infected animals. Upon infection, we observed a marked recruitment of cells in the spleen and in the peritoneal cavity of infected animals, which increased with time of infection (Fig 4A and 4B, respectively). Among these cells, DCs (defined as CD11chi F4/80- cells) were recruited both at the spleen and the peritoneum since the first wpi, and their number augmented with the course of infection (Fig 4A and 4B). In spite of the fact that all DCs were MHC class II positive, they presented remarkable decreased levels of MHCII expression (Fig 4C–4E). Indeed, splenic DCs presented around 50% reduction of MHCII expression since the first wpi together with lower levels of CD40 on their surface (S1B Fig). MHC class II- or CD40-decreased expression on DC surface was not modified when infecting animals with higher parasite dose (S1B Fig). Moreover, from the second wpi, an increase of IL-10 secreting splenic DCs was evidenced (Figs 4D and S2). Strikingly, IL-12+ DCs also augmented in the spleen (Fig 4D). DCs recruited into the peritoneum also reduced the expression of MHC class II (Fig 4E) while the expression of CD80 and CD86 was increased (S1C Fig). There was also an increase of IL-10 secreting DCs in the peritoneal cavity, while IL-12 secreting DCs remained very low in the peritoneum (Figs 4E and S2).

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