Genotype-Specific Neutralization and Protection by Antibodies against Dengue Virus Type 3

Abstract

Dengue viruses (DENV) comprise a family of related positive-strand RNA viruses that infect up to 100 million people annually. Currently, there is no approved vaccine or therapy to prevent infection or diminish disease severity. Protection against DENV is associated with the development of neutralizing antibodies that recognize the viral envelope (E) protein. Here, with the goal of identifying monoclonal antibodies (MAbs) that can function as postexposure therapy, we generated a panel of 82 new MAbs against DENV-3, including 24 highly neutralizing MAbs. Using yeast surface display, we localized the epitopes of the most strongly neutralizing MAbs to the lateral ridge of domain III (DIII) of the DENV type 3 (DENV-3) E protein. While several MAbs functioned prophylactically to prevent DENV-3-induced lethality in a stringent intracranial-challenge model of mice, only three MAbs exhibited therapeutic activity against a homologous strain when administered 2 days after infection. Remarkably, no MAb in our panel protected prophylactically against challenge by a strain from a heterologous DENV-3 genotype. Consistent with this, no single MAb neutralized efficiently the nine different DENV-3 strains used in this study, likely because of the sequence variation in DIII within and between genotypes. Our studies suggest that strain diversity may limit the efficacy of MAb therapy or tetravalent vaccines against DENV, as neutralization potency generally correlated with a narrowed genotype specificity.Dengue viruses (DENV) cause the most common arthropod-borne viral infection in humans worldwide, with ϳ50 million to 100 million people infected annually and ϳ2.5 billion people at risk (13, 61). Infection by four closely related but serologically distinct viruses of the Flavivirus genus (DENV serotypes 1, 2, 3, and 4 [DENV-1 to -4, respectively]) cause dengue fever (DF), an acute, self-limiting, yet severe, febrile illness, or dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS), a potentially fatal syndrome characterized by vascular leakage and a bleeding diathesis. Specific treatment or prevention of dengue disease is supportive, as there is no approved antiviral therapy or vaccine available.DENV has an ϳ11-kb, single-stranded, positive-sense RNA genome that is translated into a polyprotein and is cleaved posttranslationally into three structural (envelope [E], pre/ membrane [prM], and capsid [C]) and seven nonstructural (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins. The three structural proteins encapsidate a single infectious RNA of the DENV genome, whereas the nonstructural proteins have key enzymatic or regulatory functions that promote replication. Additionally, several DENV proteins are multifunctional and modulate cell-intrinsic and cell-extrinsic host immune responses (10).Most flavivirus-neutralizing antibodies recognize the structural E protein (reviewed in reference 40). Based on X-ray crystallographic analysis (32, 33), the DENV E protein is divided into three domains: domain I (DI), which is an 8-strand...

The pathogenesis of dengue

“…121 Recently, evidence of antigenic differences between genotypes of the same serotype has emerged. 122,123 To date these differences have been elucidated using mAbs specific to the E protein and it remains to be seen whether such differences are present in the face of polyclonal immune sera. Prospective cohort studies that can follow the introduction of different DEN virus genotypes into the same population are needed to understand the clinical and epidemiological significance of antigenic variation between DEN virus genotypes.…”

Recombinant vesicular stomatitis virus-based dengue-2 vaccine candidate induces humoral response and protects mice against lethal infection

“…But, it has been demonstrated that dengue neutralization by antibodies could vary up to 10 times among different genotypes of the same serotype, this is one of the hypothesis of the reduced CYD 23 vaccine efficacy and might have an impact on the future of dengue vaccines. 8,17,[24][25][26][27] The prM/E expressed in VSV-DENV-2 belongs to the NGC Asian genotype 2 and the DENV-2 TR1751 used on the neutralization and challenge experiments is an American genotype. Although they belong to different genotypes and share 93% of identity, 28 the immunity raised by VSV-DENV-2 NGC was sufficient to neutralize the heterologous American genotype TR1751 infection in vivo and in vitro.…”

Genotype-specific neutralization determinants in envelope protein: implications for the improvement of Japanese encephalitis vaccine

“…These genotype-dependent epitopes are JEV-specific and completely different from those of DENV (Bernardo et al, 2009;Brien et al, 2010;Kochel et al, 2002;Shrestha et al, 2010;Wong et al, 2007). Previous studies using mAbs indicated that the potent neutralizing capacity was impacted by the genotype-dependent conformational change/exposure of the CC9 loop epitope in DIII (Austin et al, 2012).…”