High affinity nanobodies against the Trypanosome brucei VSG are potent trypanolytic agents that block endocytosis
| Autor: | Jeremy N. Skepper, Dirk Saerens, Senthil Kumar A. Natesan, Lea Brys, Mark C. Field, Alexandros Nikolaou, Serge Muyldermans, Stefan Magez, Etienne Pays, David Perez-Morga, Katja Conrath, Benoit Stijlemans, Patrick De Baetselier, Guy Caljon |
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| Přispěvatelé: | Cellular and Molecular Immunology, Molecular and Biochemical Pharmacology |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Models
Molecular Trypanocidal Agents -- pharmacology -- therapeutic use Antibody Affinity Antibodies Protozoan Epitope Mice Trypanosome brucei Down-Regulation -- drug effects Molecular Cell Biology Biology (General) Cells Cultured chemistry.chemical_classification 0303 health sciences biology trypanosomiasis therapeutics Trypanosoma brucei brucei -- immunology -- metabolism -- physiology -- ultrastructure Sciences bio-médicales et agricoles Trypanocidal Agents nanobodies Endocytosis 3. Good health Cell biology Antibodies Protozoan -- immunology -- pharmacology -- therapeutic use Antibody Endocytosis -- drug effects Variant Surface Glycoproteins Trypanosoma Sciences exactes et naturelles Research Article Biotechnology trypanolytic agent Trypanosomiasis African -- immunology -- metabolism -- therapy QH301-705.5 Immunology Molecular Sequence Data Trypanosoma brucei brucei Down-Regulation Trypanosoma brucei Microbiology Models Biological 03 medical and health sciences Virology parasitic diseases Genetics Antigenic variation Animals Humans Amino Acid Sequence variant-specific surface glycoprotein Molecular Biology Biology 030304 developmental biology 030306 microbiology Variant Surface Glycoproteins Trypanosoma -- immunology RC581-607 biology.organism_classification Molecular biology Complement system Mice Inbred C57BL Trypanosomiasis African chemistry biology.protein Trypanosoma Nanoparticles Parasitology Immunologic diseases. Allergy Glycoprotein |
| Zdroj: | Vrije Universiteit Brussel PLoS Pathogens, Vol 7, Iss 6, p e1002072 (2011) PLoS Pathogens P L o S Pathogens, 7 (6 |
| Popis: | The African trypanosome Trypanosoma brucei, which persists within the bloodstream of the mammalian host, has evolved potent mechanisms for immune evasion. Specifically, antigenic variation of the variant-specific surface glycoprotein (VSG) and a highly active endocytosis and recycling of the surface coat efficiently delay killing mediated by anti-VSG antibodies. Consequently, conventional VSG-specific intact immunoglobulins are non-trypanocidal in the absence of complement. In sharp contrast, monovalent antigen-binding fragments, including 15 kDa nanobodies (Nb) derived from camelid heavy-chain antibodies (HCAbs) recognizing variant-specific VSG epitopes, efficiently lyse trypanosomes both in vitro and in vivo. This Nb-mediated lysis is preceded by very rapid immobilisation of the parasites, massive enlargement of the flagellar pocket and major blockade of endocytosis. This is accompanied by severe metabolic perturbations reflected by reduced intracellular ATP-levels and loss of mitochondrial membrane potential, culminating in cell death. Modification of anti-VSG Nbs through site-directed mutagenesis and by reconstitution into HCAbs, combined with unveiling of trypanolytic activity from intact immunoglobulins by papain proteolysis, demonstrates that the trypanolytic activity of Nbs and Fabs requires low molecular weight, monovalency and high affinity. We propose that the generation of low molecular weight VSG-specific trypanolytic nanobodies that impede endocytosis offers a new opportunity for developing novel trypanosomiasis therapeutics. In addition, these data suggest that the antigen-binding domain of an anti-microbial antibody harbours biological functionality that is latent in the intact immunoglobulin and is revealed only upon release of the antigen-binding fragment. Evaluation Studies Journal Article Research Support, Non-U.S. Gov't SCOPUS: ar.j info:eu-repo/semantics/published |
| Databáze: | OpenAIRE |
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