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Antibody trapping: A novel mechanism of parasite immune evasion by the trematode Echinostoma caproni
- Source :
- PLoS Neglected Tropical Diseases, PLoS Neglected Tropical Diseases, Vol 11, Iss 7, p e0005773 (2017)
- Publication Year :
- 2017
- Publisher :
- Public Library of Science, 2017.
-
Abstract
- 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 immunofluorescence 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.<br />Author summary Helminthiases are highly prevalent neglected tropical diseases, affecting millions of people worldwide, mainly in the poorest regions. The lack of vaccines against these infections is one of the major constraints in the current parasitology and massive efforts are being done in that direction. Herein, we present a potential mechanism for parasite immune evasion consisting in trapping of surface-bound antibodies within the excretory/secretory products that are deposited over the parasite. This mechanism is aided by parasite-derived proteases, well documented virulence factors that degrade the entrapped antibodies. Altogether, this parasite strategy may serve to minimize the antibody-mediated response and promote the development of chronic infections. The present study has been done using the model trematode Echinostoma caproni, though is expected to work in other helminths, even in other groups of extracellular pathogens. This opens new expectative to better understanding of host-parasite interactions and susceptibility to helminth infections. Therefore, the results presented in this manuscript may contribute to the basis of anti-helminth vaccine development.
- Subjects :
- 0301 basic medicine
Male
Physiology
Antibody Response
Pathogenesis
Pathology and Laboratory Medicine
Biochemistry
Mice
Immune Physiology
Echinostoma
Medicine and Health Sciences
Parasite hosting
Enzyme-Linked Immunoassays
Microscopy, Immunoelectron
Immune Response
Echinostomiasis
Immune System Proteins
biology
lcsh:Public aspects of medicine
Proteases
030108 mycology & parasitology
Enzymes
Infectious Diseases
Helminth Infections
Host-Pathogen Interactions
Trematoda
Antibody
Cellular Structures and Organelles
Research Article
Protein Binding
lcsh:Arctic medicine. Tropical medicine
lcsh:RC955-962
Immunology
Antibodies, Helminth
Context (language use)
Research and Analysis Methods
Antibodies
03 medical and health sciences
Immune system
Parasitic Diseases
Animals
Secretion
Vesicles
Immunoassays
Immune Evasion
Public Health, Environmental and Occupational Health
Biology and Life Sciences
Proteins
lcsh:RA1-1270
Cell Biology
biology.organism_classification
Virology
Disease Models, Animal
030104 developmental biology
Microscopy, Fluorescence
Proteolysis
biology.protein
Immunologic Techniques
Enzymology
Subjects
Details
- Language :
- English
- ISSN :
- 19352735 and 19352727
- Volume :
- 11
- Issue :
- 7
- Database :
- OpenAIRE
- Journal :
- PLoS Neglected Tropical Diseases
- Accession number :
- edsair.doi.dedup.....6d42f64f4cade5ceb4a073327d230123