== Source, binding specificity, epitope, and neutralizing potency of human monoclonal antibodies in this studye Primary or secondary DENV infection and the serotype infecting the patients were determined as reported previously (41)

== Source, binding specificity, epitope, and neutralizing potency of human monoclonal antibodies in this studye Primary or secondary DENV infection and the serotype infecting the patients were determined as reported previously (41). GR, group reactive; CR, complex reactive; TS, type specific. The domain was based on the location of the epitope residues or the binding to recombinant DI/II or DIII reported previously (21,23,27,31). Epitope residues were reported previously or identified in this study (DV470.12, 87.1, 28.1, 143.6, 291.3, 291.7, 378.12). D1, DENV1; D2, DENV2; D3, DENV3. == FIG 1. 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. Amsilarotene (TAC-101) KEYWORDS:dengue virus, envelope, mature particles, monoclonal antibody, neutralization == 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 Amsilarotene (TAC-101) 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 NT50states 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 Amsilarotene (TAC-101) 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. IMPORTANCEWith 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. == INTRODUCTION == Dengue virus (DENV) belongs to theFlavivirusgenus of theFlaviviridaefamily. There are four serotypes (DENV serotype 1 [DENV1], DENV2, DENV3, and DENV4) that cause the most common and significant arboviral disease in humans (1). Approximately 390 million DENV infections occur annually, with 25% of these being apparent Amsilarotene (TAC-101) infections, including dengue fever and the severe forms of disease, dengue hemorrhagic fever and dengue shock syndrome (14). Although the live-attenuated chimeric yellow fever-dengue vaccine Dengvaxia has been licensed in several countries, it is recommended only for persons who have experienced previous DENV infection. The moderate efficacy (60%) of Dengvaxia in the presence of Amsilarotene (TAC-101) neutralizing antibodies during phase 2b and 3 Rabbit Polyclonal to Smad1 (phospho-Ser465) trials, its lower efficacy among dengue-naive individuals than among dengue-experienced individuals (40 versus 80%), and the increased risk of hospitalization and severe dengue among young vaccinated children highlight the need for a better understanding of humoral responses following natural DENV infection (59). DENV contains a positive-sense single-stranded RNA genome encoding one polyprotein, which is cleaved into three structural proteins, the capsid, premembrane (prM), and envelope (E) proteins, and seven nonstructural proteins (10). E protein, present on the surface of the virion, mediates virus entry and is the major target of neutralizing antibodies (4,10). The ectodomain of E protein has three domains. Domain I (DI) is located in the center; domain II (DII), an elongated domain containing the fusion loop (FL) at its tip, is involved in dimerization and membrane fusion; and domain III (DIII), an immunoglobulin-like domain, is involved in receptor binding and stabilization of trimers during fusion (1013). In theFlavivirusgenus, there are several serocomplexes, including the DENV serocomplex, the Japanese encephalitis virus serocomplex, the tick-borne encephalitis virus serocomplex, and yellow fever virus as a single member. Anti-E antibodies that recognize members of two or more serocomplexes, members within the same serocomplex, or a single member are categorized as group-reactive (GR), complex-reactive (CR), or type-specific (TS) antibodies,.

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