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    Fasciola hepatica infection downregulates Th1 responses in mice


    O'neill, Sandra M., Brady, Miriam T., Callanan, John J., Mulcahy, Grace, Joyce, Patrick, Mills, Kingston H.G. and Dalton, John P. (2000) Fasciola hepatica infection downregulates Th1 responses in mice. Parasite Immunology, 22 (3). pp. 147-155. ISSN 0141-9838

    Abstract

    Immune responses induced with helminth parasites have been extensively studied, but there is limited information on those to Fasciola hepatica , especially on the subtype of T cell induced with this parasite. We investigated the local and systemic T cell responses of different strains of mice following oral infection with doses of metacercariae from F. hepatica . Spleen cells from BALB/c and 129Sv/Ev mice given a low‐dose (5 metacercariae) infection exhibited a Th2 response, producing high levels of the cytokines IL‐4 and IL‐5, and low levels of IFN‐γ and IL‐2. In contrast, C57BL/6 mice showed a mixed Th1/Th2 response. A more marked polarization to a Th2 response was observed in BALB/c, 129Sv/Ev exposed to a high‐dose (15 metacercariae) infection and the C57BL/6 mice also exhibited a clear Th2 response. IL‐4 defective (IL‐4 −/− ) C57BL/6 mice infected with 5 metacercariae produced less IFN‐γ and more IL‐5 compared to their wild‐type C57BL/6 counterparts, suggesting that IL‐4 is important in establishing the Th2 type response in murine fasciolosis. However, the secretion of IFN‐γ and IL‐2 was completely suppressed in the high‐dose infection and this was also observed in IL‐4 −/− mice. Thus, liver flukes may secrete molecules that downregulate Th1 responses. T cell responses in the mesenteric (MLN) and hepatic lymph nodes (HLN) were also examined since newly excysted juveniles infect through the intestinal wall of their host before migrating to the hepatic tissue. Cells from both MLN and HLN secreted higher levels of IL‐4 and IL‐5 compared to spleen cells. We also observed a difference in cytokine profiles secreted by the MLN and HLN, which may reflect responses to antigens liberated by newly excysted juveniles and hepatic stage parasites, respectively .
    Item Type: Article
    Keywords: Fasciola hepatica; helminth; immune responses; cytokines; Th cells;
    Academic Unit: Faculty of Science and Engineering > Biology
    Item ID: 20861
    Identification Number: 10.1046/j.1365-3024.2000.00290.x
    Depositing User: IR Editor
    Date Deposited: 25 Nov 2025 15:45
    Journal or Publication Title: Parasite Immunology
    Publisher: Wiley
    Refereed: Yes
    Related URLs:
    Use Licence: This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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