Abstract
Fungal pathogens have evolved a broad suite of strategies aiming at evading the host immune response. Amphibians are globally infected by the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd) and, while robust innate immune defences have been characterised, there is little evidence for the existence of effective adaptive immunity. We determine the immune response of the common midwife toad following challenge by Bd as larvae. Immune function was described for both the cell-mediated and antibody-mediated immune responses following infectious challenge as larval amphibians. While there were no significant differences in the ratio of neutrophils/lymphocytes between infected and uninfected individuals, early exposure of tadpoles to Bd significantly dampened the levels of circulating immunoglobulins (IgM and IgY) in the serum of juveniles after metamorphosis. Our results show that Bd immunosuppresses amphibians when infection occurs as larvae with potentially broad effects on the remodelling of immunity during metamorphosis.
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Acknowledgements
Belén Patiño (University Complutense of Madrid) helped with fungus culture. Robert Jacques (University of Rochester Medical Center, NY) provided monoclonal antibodies. Yolanda Jiménez (MNCN-CSIC) helped with the indirect enzyme-linked immunosorbent assay. Ma. Carmen Aceña Fabián (Veterinary Faculty of Zaragoza) helped with blood smears staining and white blood cell identification.
Funding
AFL was funded by Fundación General CSIC and Banco Santander. MCF was funded by the Leverhulme Trust RPG 2014 273.
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All animal experiments were conducted in compliance of the Directive 2010/63/EU for the protection of animals used for scientific purposes in facilities of the regional government and under permit of the competent authorities (permits 10/032921.9/12 and 10/071126.9/13, Consejería de Medio Ambiente of Madrid).
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Fernández-Loras, A., Fernández-Beaskoetxea, S., Arriero, E. et al. Early exposure to Batrachochytrium dendrobatidis causes profound immunosuppression in amphibians. Eur J Wildl Res 63, 99 (2017). https://doi.org/10.1007/s10344-017-1161-y
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DOI: https://doi.org/10.1007/s10344-017-1161-y