Dominguez, M.F., González-Miguel, J., Carmona, C., Dalton, J.P., Cwiklinski, K., Tort, J., Siles-Lucas, M. Low allelic diversity in vaccine candidates genes from different locations sustain hope for Fasciola hepatica immunization. Veterinary ParasitologyVolume 258, 15 July 2018, Pages 46-52
In this paper, phenotypic differences in vaccine candidate sequences amongst Fasciola hepatica parasites used in the challenge infections for vaccination trials have been studied. Vaccination trials that have been performed mainly in ruminants over the last 30 years, show high variability in the achieved protection and are not yet ready for commercialisation. Phenotypic differences have been explored as a potential cause for this variation. The isolates of F. hepatica compiled to establish a F hepatica Biobank were used for this study, focusing in the variation of vaccine candidates that are important in host-parasite interactions and are the focus of the H2020 PARAGONE vaccine project, namely FhCL1, FhCL2, FhPrx, FhLAP and FhHDM. Our results show that F. hepatica exhibits a high level of conservation in the sequences encoding each of these proteins. The consequential low variability in these vaccine candidates amongst parasites from different geographical regions reinforces the idea that they would be suitable immunogens against liver fluke isolates worldwide.