scholarly journals The Potent and Broadly Neutralizing Human Dengue Virus-Specific Monoclonal Antibody 1C19 Reveals a Unique Cross-Reactive Epitope on the bc Loop of Domain II of the Envelope Protein

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Scott A. Smith ◽  
A. Ruklanthi de Alwis ◽  
Nurgun Kose ◽  
Eva Harris ◽  
Kristie D. Ibarra ◽  
...  

ABSTRACTFollowing natural dengue virus (DENV) infection, humans produce some antibodies that recognize only the serotype of infection (type specific) and others that cross-react with all four serotypes (cross-reactive). Recent studies with human antibodies indicate that type-specific antibodies at high concentrations are often strongly neutralizingin vitroand protective in animal models. In general, cross-reactive antibodies are poorly neutralizing and can enhance the ability of DENV to infect Fc receptor-bearing cells under some conditions. Type-specific antibodies at low concentrations also may enhance infection. There is an urgent need to determine whether there are conserved antigenic sites that can be recognized by cross-reactive potently neutralizing antibodies. Here, we describe the isolation of a large panel of naturally occurring human monoclonal antibodies (MAbs) directed to the DENV domain II fusion loop (FL) envelope protein region from subjects following vaccination or natural infection. Most of the FL-specific antibodies exhibited a conventional phenotype, characterized by low-potency neutralizing function and antibody-dependent enhancing activity. One clone, however, recognized the bc loop of domain II adjacent to the FL and exhibited a unique phenotype of ultrahigh potency, neutralizing all four serotypes better than any other previously described MAb recognizing this region. This antibody not only neutralized DENV effectively but also competed for binding against the more prevalent poor-quality antibodies whose binding was focused on the FL. The 1C19 human antibody could be a promising component of a preventative or therapeutic intervention. Furthermore, the unique epitope revealed by 1C19 suggests a focus for rational vaccine design based on novel immunogens presenting cross-reactive neutralizing determinants.IMPORTANCEWith no effective vaccine available, the incidence of dengue virus (DENV) infections worldwide continues to rise, with more than 390 million infections estimated to occur each year. Due to the unique roles that antibodies are postulated to play in the pathogenesis of DENV infection and disease, there is consensus that a successful DENV vaccine must protect against all four serotypes. If conserved epitopes recognized by naturally occurring potently cross-neutralizing human antibodies could be identified, monovalent subunit vaccine preparations might be developed. We characterized 30 DENV cross-neutralizing human monoclonal antibodies (MAbs) and identified one (1C19) that recognized a novel conserved site, known as the bc loop. This antibody has several desirable features, as it neutralizes DENV effectively and competes for binding against the more common low-potency fusion loop (FL) antibodies, which are believed to contribute to antibody-mediated disease. To our knowledge, this is the first description of a potent serotype cross-neutralizing human antibody to DENV.

2012 ◽  
Vol 87 (1) ◽  
pp. 52-66 ◽  
Author(s):  
J. M. Costin ◽  
E. Zaitseva ◽  
K. M. Kahle ◽  
C. O. Nicholson ◽  
D. K. Rowe ◽  
...  

2015 ◽  
Vol 90 (2) ◽  
pp. 780-789 ◽  
Author(s):  
Scott A. Smith ◽  
Usha K. Nivarthi ◽  
Ruklanthi de Alwis ◽  
Nurgun Kose ◽  
Gopal Sapparapu ◽  
...  

ABSTRACTThe proposed antibody-dependent enhancement (ADE) mechanism for severe dengue virus (DENV) disease suggests that non-neutralizing serotype cross-reactive antibodies generated during a primary infection facilitate entry into Fc receptor bearing cells during secondary infection, resulting in enhanced viral replication and severe disease. One group of cross-reactive antibodies that contributes considerably to this serum profile target the premembrane (prM) protein. We report here the isolation of a large panel of naturally occurring human monoclonal antibodies (MAbs) obtained from subjects following primary DENV serotype 1, 2, or 3 or secondary natural DENV infections or following primary DENV serotype 1 live attenuated virus vaccination to determine the antigenic landscape on the prM protein that is recognized by human antibodies. We isolated 25 prM-reactive human MAbs, encoded by diverse antibody-variable genes. Competition-binding studies revealed that all of the antibodies bound to a single major antigenic site on prM. Alanine scanning-based shotgun mutagenesis epitope mapping studies revealed diverse patterns of fine specificity of various clones, suggesting that different antibodies use varied binding poses to recognize several overlapping epitopes within the immunodominant site. Several of the antibodies interacted with epitopes on both prM and E protein residues. Despite the diverse genetic origins of the antibodies and differences in the fine specificity of their epitopes, each of these prM-reactive antibodies was capable of enhancing the DENV infection of Fc receptor-bearing cells.IMPORTANCEAntibodies may play a critical role in the pathogenesis of enhanced DENV infection and disease during secondary infections. A substantial proportion of enhancing antibodies generated in response to natural dengue infection are directed toward the prM protein. The fine specificity of human prM antibodies is not understood. Here, we isolated a panel of dengue prM-specific human monoclonal antibodies from individuals after infection in order to define the mode of molecular recognition by enhancing antibodies. We found that only a single antibody molecule can be bound to each prM protein at any given time. Distinct overlapping epitopes were mapped, but all of the epitopes lie within a single major antigenic site, suggesting that this antigenic domain forms an immunodominant region of the protein. Neutralization and antibody-dependent enhanced replication experiments showed that recognition of any of the epitopes within the major antigenic site on prM was sufficient to cause enhanced infection of target cells.


2018 ◽  
Vol 92 (23) ◽  
Author(s):  
Wen-Yang Tsai ◽  
Hui-Ling Chen ◽  
Jih-Jin Tsai ◽  
Wanwisa Dejnirattisai ◽  
Amonrat Jumnainsong ◽  
...  

ABSTRACT The four serotypes of dengue virus (DENV) cause the most important mosquito-borne viral disease in humans. The envelope (E) protein is the major target of neutralizing antibodies and contains 3 domains (domain I [DI], DII, and DIII). Recent studies reported that human monoclonal antibodies (MAbs) recognizing DIII, the D1/DII hinge, the E-dimer epitope, or a quaternary epitope involving DI/DII/DIII are more potently neutralizing than those recognizing the fusion loop (FL) of DII. Due to inefficient cleavage of the premembrane protein, DENV suspensions consist of a mixture of mature, immature, and partially immature particles. We investigated the neutralization and binding of 22 human MAbs to DENV serotype 1 (DENV1) virions with differential maturation status. Compared with FL MAbs, DIII, DI/DII hinge, and E-dimer epitope MAbs showed higher maximum binding and avidity to mature particles relative to immature particles; this feature may contribute to the strong neutralizing potency of such MAbs. FL-specific MAbs required 57 to 87% occupancy on mature particles to achieve half-maximal neutralization (NT50), whereas the potently neutralizing MAbs achieved NT50 states at 20 to 38% occupancy. Analysis of the MAb repertoire and polyclonal sera from patients with primary DENV1 infection supports the immunodominance of cross-reactive anti-E antibodies over type-specific antibodies. After depletion with viral particles from a heterologous DENV serotype, the type-specific neutralizing antibodies remained and showed binding features shared by potent neutralizing MAbs. Taken together, these findings suggest that the use of homogeneous mature DENV particles as an immunogen may induce more potent neutralizing antibodies against DENV than the use of immature or mixed particles. IMPORTANCE With an estimated 390 million infections per year, the four serotypes of dengue virus (DENV) cause the most important mosquito-borne viral disease in humans. The dengue vaccine Dengvaxia was licensed; however, its low efficacy among dengue-naive individuals and increased risk of causing severe dengue in children highlight the need for a better understanding of the role of human antibodies in immunity against DENV. DENV suspensions contain mature, immature, and partially immature particles. We investigated the binding of 22 human monoclonal antibodies (MAbs) to the DENV envelope protein on particles with different maturation states. Potently neutralizing MAbs had higher relative maximum binding and avidity to mature particles than weakly neutralizing MAbs. This was supported by analysis of MAb repertoires and polyclonal sera from patients with primary DENV infection. Together, these findings suggest that mature particles may be the optimal form of presentation of the envelope protein to induce more potent neutralizing antibodies against DENV.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jean-François Bruxelle ◽  
Tess Kirilenko ◽  
Nino Trattnig ◽  
Yiqiu Yang ◽  
Matteo Cattin ◽  
...  

AbstractThe occurrence of oligomannose-specific broadly neutralizing antibodies (bnAbs) has spurred efforts to develop immunogens that can elicit similar antibodies. Here, we report on the antigenicity and immunogenicity of a CRM197-conjugate of a previously reported oligomannose mimetic. Oligomannose-specific bnAbs that are less dependent on interactions with the HIV envelope protein sequence showed strong binding to the glycoconjugates, with affinities approximating those reported for their cognate epitope. The glycoconjugate is also recognized by inferred germline precursors of oligomannose-specific bnAbs, albeit with the expected low avidity, supporting its potential as an immunogen. Immunization of human-antibody transgenic mice revealed that only a TLR4-stimulating adjuvant formulation resulted in antibodies able to bind a panel of recombinant HIV trimers. These antibodies bound at relatively modest levels, possibly explaining their inability to neutralize HIV infectivity. Nevertheless, these findings contribute further to understanding conditions for eliciting HIV-cross-reactive oligomannose-specific antibodies and inform on next steps for improving on the elicited response.


2006 ◽  
Vol 80 (2) ◽  
pp. 891-899 ◽  
Author(s):  
Zhongyu Zhu ◽  
Antony S. Dimitrov ◽  
Katharine N. Bossart ◽  
Gary Crameri ◽  
Kimberly A. Bishop ◽  
...  

ABSTRACT Hendra virus (HeV) and Nipah virus (NiV) are closely related emerging viruses comprising the Henipavirus genus of the Paramyxovirinae. Each has a broad species tropism and can cause disease with high mortality in both animal and human hosts. These viruses infect cells by a pH-independent membrane fusion event mediated by their attachment (G) and fusion (F) envelope glycoproteins (Envs). Seven Fabs, m101 to -7, were selected for their significant binding to a soluble form of Hendra G (sG) which was used as the antigen for panning of a large naïve human antibody library. The selected Fabs inhibited, to various degrees, cell fusion mediated by the HeV or NiV Envs and virus infection. The conversion of the most potent neutralizer of infectious HeV, Fab m101, to immunoglobulin G1 (IgG1) significantly increased its cell fusion inhibitory activity: the 50% inhibitory concentration was decreased more than 10-fold to approximately 1 μg/ml. The IgG1 m101 was also exceptionally potent in neutralizing infectious HeV; complete (100%) neutralization was achieved with 12.5 μg/ml, and 98% neutralization required only 1.6 μg/ml. The inhibition of fusion and infection correlated with binding of the Fabs to full-length G as measured by immunoprecipitation and less with binding to sG as measured by enzyme-linked immunosorbent assay and Biacore. m101 and m102 competed with the ephrin-B2, which we recently identified as a functional receptor for both HeV and NiV, indicating a possible mechanism of neutralization by these antibodies. The m101, m102, and m103 antibodies competed with each other, suggesting that they bind to overlapping epitopes which are distinct from the epitopes of m106 and m107. In an initial attempt to localize the epitopes of m101 and m102, we measured their binding to a panel of 11 G alanine-scanning mutants and identified two mutants, P185A and Q191 K192A, which significantly decreased binding to m101 and one, G183, which decreased binding of m102 to G. These results suggest that m101 to -7 are specific for HeV or NiV or both and exhibit various neutralizing activities; they are the first human monoclonal antibodies identified against these viruses and could be used for treatment, prophylaxis, and diagnosis and as research reagents and could aid in the development of vaccines.


1988 ◽  
Vol 34 (9) ◽  
pp. 1681-1688 ◽  
Author(s):  
P H Ehrlich ◽  
Z A Moustafa ◽  
J C Justice ◽  
K E Harfeldt ◽  
I K Gadi ◽  
...  

Abstract Human monoclonal antibodies, owing to their decreased immunogenicity, are expected to be an improvement over mouse monoclonal antibodies for in vivo therapy. Human and primate monoclonal antibodies are best produced with a human x mouse heteromyeloma. Several human chromosomes are stable in the human x (human x mouse) hybrids. Chimpanzee anti-digoxin monoclonal antibodies were prepared and characterized. Because they are structurally very similar to human antibodies, they should be well tolerated in humans. The anti-digoxin antibodies can be used for therapy of extreme overdoses or as an in vivo diagnostic tool for slight overdoses. Because the advantage of using human monoclonal antibodies is their lack of immunogenicity, preparation of the antibody must be scrupulous so as not to introduce extraneous immunogens. Analysis to ensure the purity of the preparation can be complicated by the presence of high concentrations of the antibody and the low levels of contamination that must be detected. We describe a Western blot assay for Protein A that is sensitive even in the presence of human IgG.


2012 ◽  
Vol 423 (4) ◽  
pp. 867-872 ◽  
Author(s):  
Chayanee Setthapramote ◽  
Tadahiro Sasaki ◽  
Orapim Puiprom ◽  
Kriengsak Limkittikul ◽  
Pannamthip Pitaksajjakul ◽  
...  

2011 ◽  
Vol 19 (1) ◽  
pp. 73-78 ◽  
Author(s):  
Lidong Liu ◽  
Kun Wen ◽  
Jie Li ◽  
Dongmei Hu ◽  
Yanfen Huang ◽  
...  

ABSTRACTThe plaque reduction neutralization test (PRNT) is used widely to measure the neutralization activity of anti-dengue virus (DENV) antibodies, but it is time-consuming and labor-intensive and has low sample throughput. For fast and convenient measurement of neutralizing antibodies, especially in evaluating the efficiency of the DENV vaccines on a large scale, a new method is needed to replace PRNT. In recent decades, several microneutralization assays have been developed to overcome the limitations of PRNT. In the present study, we evaluated one of these, the enzyme-linked immunospot microneutralization test (ELISPOT-MNT), in comparison with PRNT. ELISPOT-MNT is performed in 96-well format, and the plaques are developed after 2 to 4 days using an ELISA to transform them into spots, which are detected automatically with an ELISPOT instrument. The assay is faster than PRNT, has a high throughput, and is more objective. We used 10 monoclonal antibodies (MAbs) against domain III of the DENV envelope protein (EDIII) to evaluate the two assays; all of these MAbs cross-react with all four serotypes of DENV as measured by immunofluorescence assay. The two neutralization assays were performed simultaneously to measure the 50% inhibitory concentration (IC50) of these MAbs. Using PRNT as the reference and treating IC50values higher than 50 μg/ml of MAbs as negative, ELISPOT-MNT showed a sensitivity of 95.6% and specificity of 88.24% when 10 MAbs were tested against four DENV serotype strains. A good correlation (R2= 0.672;P= 0.000) was observed between the two assays, making ELISPOT-MNT a potentially valuable method for measure of neutralizing antibodies against DENV.


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