Antibody trapping: a novel mechanism of parasite immune evasion by the trematode Echinostoma caproni

Cortés, Alba, Sotillo-Gallego, Javier, Muñoz-Antolí, Carla, Molina-Durán, Javier, Esteban, J. Guillermo, and Toledo, Rafael (2017) Antibody trapping: a novel mechanism of parasite immune evasion by the trematode Echinostoma caproni. PLoS Neglected Tropical Diseases, 11 (7). e005773.

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Background: Helminth infections are among the most prevalent neglected tropical diseases, causing an enormous impact in global health and the socioeconomic growth of developing countries. In this context, the study of helminth biology, with emphasis on host-parasite interactions, appears as a promising approach for developing new tools to prevent and control these infections.

Methods/Principal findings: The role that antibody responses have on helminth infections is still not well understood. To go in depth into this issue, work on the intestinal helminth Echinostoma caproni (Trematoda: Echinostomatidae) has been undertaken. Adult parasites were recovered from infected mice and cultured in vitro. Double indirect immunofluoresce nce at increasing culture times was done to show that in vivo-bound surface antibodies become trapped within a layer of excretory/secretory products that covers the parasite. Entrapped antibodies are then degraded by parasite-derived proteases, since protease inhibitors prevent for antibody loss in culture. Electron microscopy and immunogold-labelling of secreted proteins provide evidence that this mechanism is consistent with tegument dynamics and ultrastructure, hence it is feasible to occur in vivo. Secretory vesicles discharge their content to the outside and released products are deposited over the parasite surface enabling antibody trapping.

Conclusion/Significance: At the site of infection, both parasite secretion and antibody binding occur simultaneously and constantly. The continuous entrapment of bound antibodies with newly secreted products may serve to minimize the deleterious effects of the antibody-mediated attack. This mechanism of immune evasion may aid to understand the limited effect that antibody responses have in helminth infections, and may contribute to the basis for vaccine development against these highly prevalent diseases.

Item ID: 54073
Item Type: Article (Research - C1)
ISSN: 1935-2735
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This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funders: Ministerio de Economia y Competitividad (MECD), Generalitat Valenciana (GV), Ministerio de Sanidad y Consumo (MSC)
Projects and Grants: MECD BFU2016-75639-P, GV PROMETEO2014-083 Fase II, MSC RICET ISCIII no. RD12/0018/0013
Date Deposited: 14 Jun 2018 23:23
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3202 Clinical sciences > 320211 Infectious diseases @ 100%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920109 Infectious Diseases @ 100%
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