Structure of an Antibody in Complex with Its Mucin Domain Linear Epitope That Is Protective against Ebola Virus

Olal, Daniel; Kuehne, Ana I.; Bale, Shridhar; Halfmann, Peter; Hanabusa, Takao; Fusco, Marnie L.; Lee, Jeffrey E.; King, Liam B.; Kawaoka, Yoshihiro; Dye, John M.; Saphire, Erica Ollmann

doi:10.1128/jvi.05549-11

Cited by 48 publications

(45 citation statements)

References 37 publications

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“…This assessment is based on the following observations: (i) the interaction was Ca 2ϩ dependent and was inhibited by acetylated glycans, such as GlcNAc; (ii) the ficolin-1 Y271F mutant, which had an impaired sialic acid-binding capacity, did not interact with GP; (iii) removal of the mucin-like domain of GP abolished its interaction with ficolin-1; (iv) ficolin-1 did not interact with insect cells expressing GP from which sialylated glycans were deleted; and (v) sialylated moieties are present on O-linked glycans of the MLD but are largely absent from GP N-linked glycans (62). The observed ficolin-1 binding specificity for the GP mucin domain, which contains 5 N-linked glycan addition sites and 12 to 15 O-linked glycan addition sites (63), is in accordance with our previous data showing the ficolin-1 interaction with CD43, the major sialomucin exposed at the neutrophil surface (64). The unique sialic acid-binding specificity of ficolin-1, demonstrated by our previous glycan array screening analysis (48), likely accounted for the fact that human ficolin-2 and ficolin-3 were not found to interact with EBOV GP.…”

Section: Discussionmentioning

confidence: 84%

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Enhancement of Ebola Virus Infection via Ficolin-1 Interaction with the Mucin Domain of GP Glycoprotein

Favier¹,

Gout

Reynard

et al. 2016

J Virol

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Ebola virus infection requires the surface viral glycoprotein to initiate entry into the target cells. The trimeric glycoprotein is a highly glycosylated viral protein which has been shown to interact with host C-type lectin receptors and the soluble complement recognition protein mannose-binding lectin, thereby enhancing viral infection. Similarly to mannose-binding lectin, ficolins are soluble effectors of the innate immune system that recognize particular glycans at the pathogen surface. In this study, we demonstrate that ficolin-1 interacts with the Zaire Ebola virus (EBOV) glycoprotein, and we characterized this interaction by surface plasmon resonance spectroscopy. Ficolin-1 was shown to bind to the viral glycoprotein with a high affinity. This interaction was mediated by the fibrinogen-like recognition domain of ficolin-1 and the mucin-like domain of the viral glycoprotein. Using a ficolin-1 control mutant devoid of sialic acid-binding capacity, we identified sialylated moieties of the mucin domain to be potential ligands on the glycoprotein. In cell culture, using both pseudotyped viruses and EBOV, ficolin-1 was shown to enhance EBOV infection independently of the serum complement. We also observed that ficolin-1 enhanced EBOV infection on human monocyte-derived macrophages, described to be major viral target cells,. Competition experiments suggested that although ficolin-1 and mannose-binding lectin recognized different carbohydrate moieties on the EBOV glycoprotein, the observed enhancement of the infection likely depended on a common cellular receptor/partner. In conclusion, ficolin-1 could provide an alternative receptor-mediated mechanism for enhancing EBOV infection, thereby contributing to viral subversion of the host innate immune system. E bola virus (EBOV), a member of the Filoviridae family, can cause a severe, often fatal, hemorrhagic fever (HF) in humans and nonhuman primates (1). The first Ebolavirus species was discovered in 1976 in the Democratic Republic of Congo (previously called Zaire), near the Ebola River (2). Subsequently, 28 outbreaks appeared sporadically until March 2014, when the most devastating outbreak occurred in western Africa, including the countries of Guinea, Liberia, and Sierra Leone (3-6). Most outbreaks are caused by the Zaire Ebola virus subspecies (7), which is the most pathogenic (case fatality rate, up to 90%). EBOV is classified in the category A agents of the Centers for Disease Control and Prevention (CDC) because it represents a substantial threat to public health, and consequently, its handling requires a biosafety level 4 (BSL-4) laboratory. The development of effective therapies against EBOV became an urgent priority during the spread of the most recent epidemics throughout Africa, which, in addition to causing the loss of thousands of human lives, caused economic and social instability (8).The trimeric transmembrane glycoprotein (GP) of EBOV plays a crucial role in EBOV infection by mediating its cellular attachment and entry into host cells (9, 1...

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Section: Discussionmentioning

confidence: 84%

“…However, the removal of MLD from immunizing virus-like particles did not alter the neutralizing antibody response (54). The MLD could also interact with protective antibodies, but the epitopes identified so far have been unglycosylated peptides (63).…”

Section: Discussionmentioning

confidence: 99%

Enhancement of Ebola Virus Infection via Ficolin-1 Interaction with the Mucin Domain of GP Glycoprotein

Favier¹,

Gout

Reynard

et al. 2016

J Virol

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“…2D). Involvement of a ␤-turn in several peptide-antibody complexes has been reported in other X-ray structures (12)(13)(14)(15)(16)(17)(18) and in different antigenic peptides (19)(20)(21)(22). Such a structure enhances the number of interactions that can be made by an antibody to an antigen with a limited number of residues.…”

mentioning

confidence: 92%

Crystal Structure of the Conserved Amino Terminus of the Extracellular Domain of Matrix Protein 2 of Influenza A Virus Gripped by an Antibody

Cho

Schepens

Moonens

et al. 2016

J Virol

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c; Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium dWe report the crystal structure of the M2 ectodomain (M2e) in complex with a monoclonal antibody that binds the amino terminus of M2. M2e extends into the antibody binding site to form an N-terminal ␤-turn near the bottom of the paratope. This M2e folding differs significantly from that of M2e in complex with an antibody that binds another part of M2e. This suggests that M2e can adopt at least two conformations that can elicit protective antibodies. Human influenza viruses can escape antibody-mediated immunity by varying the antigenic sites in their surface antigens that are most prone to virus neutralization. Vaccines that elicit antibody responses against conserved surface-exposed antigens, such as the stem region of influenza hemagglutinin or M2e, can protect against multiple influenza virus subtypes (1). A potential clinical benefit of M2e-based vaccines can be inferred from a challenge study in human volunteers, which showed that injection of human monoclonal antibody (MAb) TCN-032 directed against M2e 1 day after inoculation of an H3N2 influenza virus resulted in reduced clinical signs and virus shedding compared to placebo treatment (2).M2e corresponds to the surface exposed amino-terminal part of M2 and is 23 amino acid residues long (3). The first nine amino acid residues of M2 are extremely conserved across all reported influenza A viruses. Human and murine M2e-specific MAbs that recognize different parts of M2e have been described, but how these interact with M2e is largely unknown (4-6). Here, we report the crystal structure of M2e in complex with a Fab fragment from a MAb that binds to the highly conserved N-terminal part of M2.The ethical committee of Ghent University approved this mouse protection study. We isolated MAb148 from a BALB/c mouse that had been immunized with a recombinant tetrameric protein of M2e using conventional hybridoma technology (7). Intraperitoneal injection of 200 g of this IgG1 MAb protected mice against a potentially lethal challenge with an H1N1 virus (Fig. 1A). To identify the epitope of MAb148, we transfected a series of alanine mutants of M2 into HEK293T cells. Transfected cells were subsequently fixed and used in an enzyme-linked immunosorbent assay (ELISA). This analysis revealed that M2 residues Ser2, Leu3, Leu4, and Thr5 are critical for MAb148 binding (Fig. 1B). A similar N-proximal epitope in M2e was reported for human MAb TCN-031 and -032 (8). ELISA analysis using wells coated with M2e peptide variants showed MAb148 binding was indifferent to most of the sequence variation in the M2e segment spanning residues 9 to 20 (Fig. 1C). However, we noted reduced binding to the M2e peptide derived from A/Hong Kong/485/97 (Fig. 1C). Also a shorter M2e peptide (SLLTEVETPIRN) proved less accessible for MAb148 binding (Fig. 1C), though in solution this peptide competed with MAb148 for binding the coating full-length M2e peptide as efficiently as full-length M2e (Fig. 1D), suggesting that reduced re...

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“…However, due to transcriptional editing, only about 20 % of GP gene product ends up as GP, the remaining 80 % representing a secreted form, sGP. A consequence is that antibodies occurring naturally during infection preferentially react with sGP, and even those that cross-react with GP are absorbed by sGP [39]. Thus, a therapeutic challenge is to find antibodies specific for viral surface GP, and a main strategy has been to study antibodies that target unique 150-amino acid mucin-like sequences in GP that extend from its top and sides and are heavily covered in both N-linked and O-linked glycans.…”

Section: Other Virusesmentioning

confidence: 99%

“…Thus, a therapeutic challenge is to find antibodies specific for viral surface GP, and a main strategy has been to study antibodies that target unique 150-amino acid mucin-like sequences in GP that extend from its top and sides and are heavily covered in both N-linked and O-linked glycans. Olal et al [39] have solved at 0.28 nm resolution the structure of a neutralizing monoclonal antibody 14G7 F ab bound to a linear epitope (residues 477-493) in this region of GP. The GP peptide adopts a tandem β-hairpin structure that extends to a depth of 1.4 nm into a pocket in the F ab V h -V L interface (Fig.…”

Section: Other Virusesmentioning

confidence: 99%

Structural aspects of molecular recognition in the immune system. Part I: Acquired immunity (IUPAC Technical Report)

Templeton

Moehle

2014

Pure and Applied Chemistry

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Humoral immunity allows the body to mount a defense against pathogens and foreign substances, and to respond with memory to subsequent exposures. The molecular participants may also recognize selfstructures, leading to attack on the body and autoimmune disease. The main players in humoral immunity are antibody-producing B lymphocytes, and several classes of T lymphocytes. This review deals with the molecular details of recognition of antigens by soluble antibodies, and of substances presented to receptors on the surfaces of T cells (TCRs). The prototype antibody consists of a dimer of dimers, two heavy (H) chains and two light (L) chains, with antigen recognition capacity lying in variable "head" regions of an H-L pair. Most crystallographic studies are done with this substructure, called a F ab fragment, bound in a soluble antigen complex. Homologous to this arrangement, the prototype TCR consists of two chains (α and β) that complex not soluble antigen, but usually a short peptide or other small molecule presented by proteins of the major histocompatibility complex. In each case a general background on the historical development of understanding the molecular recognition interface is given, followed by a number of examples of crystal structures from the recent literature that have allowed us to refine our understanding of the complex recognition process. Variations on the prototypical structures are also considered. The spectrum of recognition strategies involves interplay of lock-and-key with flexibility, varying degrees of entropic and enthalpic contributions, surface shaping by entrapped water molecules, and combinations of stabilizing hydrogen bonding, electrostatic interactions, salt bridging, and van der Waals forces. Preeminent in the recent literature are details of antibody binding to influenza A and human immunodeficiency viral antigens. Both viral antigens and attempts to understand autoimmunity are prominent in the recent TCR literature.

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Structure of an Antibody in Complex with Its Mucin Domain Linear Epitope That Is Protective against Ebola Virus

Cited by 48 publications

References 37 publications

Enhancement of Ebola Virus Infection via Ficolin-1 Interaction with the Mucin Domain of GP Glycoprotein

Enhancement of Ebola Virus Infection via Ficolin-1 Interaction with the Mucin Domain of GP Glycoprotein

Crystal Structure of the Conserved Amino Terminus of the Extracellular Domain of Matrix Protein 2 of Influenza A Virus Gripped by an Antibody

Structural aspects of molecular recognition in the immune system. Part I: Acquired immunity (IUPAC Technical Report)

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