The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival

Helminth parasites promote the development of antigen-specific anergy and regulation which often limits pathology but allows parasite survival. Parasite effectors mediating this are the subject of intense study as they may be useful as future vaccine targets. Fasciola hepatica possesses a TGF-like m...

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Main Author: Musah-Eroje, Mayowa
Format: Thesis (University of Nottingham only)
Language:English
Published: 2020
Subjects:
Online Access:https://eprints.nottingham.ac.uk/60409/
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author Musah-Eroje, Mayowa
author_facet Musah-Eroje, Mayowa
author_sort Musah-Eroje, Mayowa
building Nottingham Research Data Repository
collection Online Access
description Helminth parasites promote the development of antigen-specific anergy and regulation which often limits pathology but allows parasite survival. Parasite effectors mediating this are the subject of intense study as they may be useful as future vaccine targets. Fasciola hepatica possesses a TGF-like molecule (FhTLM), part of a larger TGF family, which play an important role in regulating parasite development and modulating host immune responses. We hypothesized that F. hepatica may utilise FhTLM to down modulate host immune responses via induction of regulatory. Consequently, in this study, the immuno-modulatory properties of FhTLM with regards to its effect on T-cell mediated immunosuppression and modulation of host immune cells and signals to benefit parasite survival were studied. The in vitro effect of FhTLM on induction of FoxP3 T-regs cells and anergic markers, PD-1, PD-L1 and CTLA-4, was studied in murine splenic CD4 T-cells. FhTLM failed to upregulate FoxP3 T-reg cells and all investigated anergic T-cell markers. However, production of IL-10, a key immunomodulatory cytokine was significantly enhanced in response to FhTLM stimulation. The interaction of FhTLM with naïve CD4 T-cells also promoted the development of inflammatory responses evidenced by enhanced production of pro-inflammatory cytokines and chemokines (TNF-α, IL-12 P70, IL-1β, IP-10, TARC, MIP-1β, IL-1ra, RANTES and CXCL12). The chemokines induced by FhTLM were biologically functional as supernatants from FhTLM stimulated cells promoted in vitro migration of both activated CD4 T-cells and eosinophils. Lastly, immune signals generated from CD4 T-cells, eosinophils and monocytes failed to support enhanced survival of newly excysted juvenile (NEJs) flukes and this response was not affected by the presence FhTLM. Whilst FhTLM did not directly modulate immune cells to promote parasite survival, induction of pro-inflammatory responses as evidenced by production of cytokines; IL-6, TNF-α, RANTES, MCP-1, Lipocalin -2, Endocan, Pentraxin-3 and ICAM-1 by LPS or IL-4-stimulated monocytes was suppressed or inhibited in the presence of FhTLM. Taken together, our data highlight an indirect mechanism used by the parasite to benefit parasite persistence and also implicate a role for IL-10 in suppression of protective host immune response to F. hepatica infection. In addition, our data also indicates that FhTLM has an anti-inflammatory potential and may have implications in the treatment of allergic or pro-inflammatory diseases.
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spelling nottingham-604092025-02-28T14:53:15Z https://eprints.nottingham.ac.uk/60409/ The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival Musah-Eroje, Mayowa Helminth parasites promote the development of antigen-specific anergy and regulation which often limits pathology but allows parasite survival. Parasite effectors mediating this are the subject of intense study as they may be useful as future vaccine targets. Fasciola hepatica possesses a TGF-like molecule (FhTLM), part of a larger TGF family, which play an important role in regulating parasite development and modulating host immune responses. We hypothesized that F. hepatica may utilise FhTLM to down modulate host immune responses via induction of regulatory. Consequently, in this study, the immuno-modulatory properties of FhTLM with regards to its effect on T-cell mediated immunosuppression and modulation of host immune cells and signals to benefit parasite survival were studied. The in vitro effect of FhTLM on induction of FoxP3 T-regs cells and anergic markers, PD-1, PD-L1 and CTLA-4, was studied in murine splenic CD4 T-cells. FhTLM failed to upregulate FoxP3 T-reg cells and all investigated anergic T-cell markers. However, production of IL-10, a key immunomodulatory cytokine was significantly enhanced in response to FhTLM stimulation. The interaction of FhTLM with naïve CD4 T-cells also promoted the development of inflammatory responses evidenced by enhanced production of pro-inflammatory cytokines and chemokines (TNF-α, IL-12 P70, IL-1β, IP-10, TARC, MIP-1β, IL-1ra, RANTES and CXCL12). The chemokines induced by FhTLM were biologically functional as supernatants from FhTLM stimulated cells promoted in vitro migration of both activated CD4 T-cells and eosinophils. Lastly, immune signals generated from CD4 T-cells, eosinophils and monocytes failed to support enhanced survival of newly excysted juvenile (NEJs) flukes and this response was not affected by the presence FhTLM. Whilst FhTLM did not directly modulate immune cells to promote parasite survival, induction of pro-inflammatory responses as evidenced by production of cytokines; IL-6, TNF-α, RANTES, MCP-1, Lipocalin -2, Endocan, Pentraxin-3 and ICAM-1 by LPS or IL-4-stimulated monocytes was suppressed or inhibited in the presence of FhTLM. Taken together, our data highlight an indirect mechanism used by the parasite to benefit parasite persistence and also implicate a role for IL-10 in suppression of protective host immune response to F. hepatica infection. In addition, our data also indicates that FhTLM has an anti-inflammatory potential and may have implications in the treatment of allergic or pro-inflammatory diseases. 2020-07-31 Thesis (University of Nottingham only) NonPeerReviewed application/pdf en arr https://eprints.nottingham.ac.uk/60409/1/Mayowa%20Musah-Eroje%20Thesis%20Final%20Version%2019-04-20.pdf Musah-Eroje, Mayowa (2020) The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival. PhD thesis, University of Nottingham. Helminth parasites Fasciola hepatica Parasites Vaccines
spellingShingle Helminth parasites
Fasciola hepatica
Parasites
Vaccines
Musah-Eroje, Mayowa
The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival
title The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival
title_full The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival
title_fullStr The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival
title_full_unstemmed The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival
title_short The Fasciola hepatica growth factor; FhTLM, and actions in immune evasion and parasite survival
title_sort fasciola hepatica growth factor; fhtlm, and actions in immune evasion and parasite survival
topic Helminth parasites
Fasciola hepatica
Parasites
Vaccines
url https://eprints.nottingham.ac.uk/60409/