Open AccessFasciola spp: Mapping of the MF6 epitope and antigenic analysis of the MF6p/HDM family of heme-binding proteins
Author(s) -
Victoria Martínez-Sernández,
María Jesús Perteguer,
Mercedes Mezo,
Marta González-Warleta,
Teresa Gárate,
M. Adela Valero,
Florencio M. Ubeira
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0188520
Subject(s) - paragonimus westermani , fasciola hepatica , epitope , biology , antigenicity , opisthorchis viverrini , fasciola , monoclonal antibody , hepatica , microbiology and biotechnology , antigen , epitope mapping , paragonimiasis , liver fluke , antibody , genetics , immunology , helminths
MF6p/FhHDM-1 is a small cationic heme-binding protein which is recognized by the monoclonal antibody (mAb) MF6, and abundantly present in parenchymal cells and secreted antigens of Fasciola hepatica . Orthologs of this protein (MF6p/HDMs) also exist in other causal agents of important foodborne trematodiasis, such as Clonorchis sinensis , Opisthorchis viverrini and Paragonimus westermani . Considering that MF6p/FhHDM-1 is relevant for heme homeostasis in Fasciola and was reported to have immunomodulatory properties, this protein is expected to be a useful target for vaccination. Thus, in this study we mapped the epitope recognized by mAb MF6 and evaluated its antigenicity in sheep. The sequence of the MF6p/FhHDM-1 ortholog from F . gigantica (MF6p/FgHDM-1) was also reported. By means of ELISA inhibitions with overlapping synthetic peptides, we determined that the epitope recognized by mAb MF6 is located within the C-terminal moiety of MF6p/FhHDM-1, which is the most conserved region of MF6p/HDMs. By immunoblotting analysis of parasite extracts and ELISA inhibitions with synthetic peptides we also determined that mAb MF6 reacted with the same intensity with F . hepatica and F . gigantica , and in decreasing order of intensity with C . sinensis , O . viverrini and P . westermani orthologs. On the contrary, mAb MF6 showed no reactivity against Dicrocoelium dendriticum and Schistosoma mansoni . The study of the recognition of peptides covering different regions of MF6p/FhHDM-1 by sera from immunized sheep revealed that the C-terminal moiety is the most antigenic, thus being of potential interest for vaccination. We also demonstrated that the production of antibodies to MF6p/FhHDM-1 in sheep infected by F . hepatica occurs relatively early and follows the same pattern as those produced against L-cathepsins.