Antibodies to Envelope Glycoprotein of Dengue Virus during the Natural Course of Infection Are Predominantly Cross-Reactive and Recognize Epitopes Containing Highly Conserved Residues at the Fusion Loop of Domain II

Abstract

The antibody response to the envelope (E) glycoprotein of dengue virus (DENV) is known to play a critical role in both protection from and enhancement of disease, especially after primary infection. However, the relative amounts of homologous and heterologous anti-E antibodies and their epitopes remain unclear. In this study, we examined the antibody responses to E protein as well as to precursor membrane (PrM), capsid, and nonstructural protein 1 (NS1) of four serotypes of DENV by Western blot analysis of DENV serotype 2-infected patients with different disease severity and immune status during an outbreak in southern Taiwan in 2002. Based on the early-convalescent-phase sera tested, the rates of antibody responses to PrM and NS1 proteins were significantly higher in patients with secondary infection than in those with primary infection. A blocking experiment and neutralization assay showed that more than 90% of anti-E antibodies after primary infection were cross-reactive and nonneutralizing against heterologous serotypes and that only a minor proportion were type specific, which may account for the type-specific neutralization activity. Moreover, the E-binding activity in sera of 10 patients with primary infection was greatly reduced by amino acid replacements of three fusion loop residues, tryptophan at position 101, leucine at position 107, and phenylalanine at position 108, but not by replacements of those outside the fusion loop of domain II, suggesting that the predominantly cross-reactive anti-E antibodies recognized epitopes involving the highly conserved residues at the fusion loop of domain II. These findings have implications for our understanding of the pathogenesis of dengue and for the future design of subunit vaccine against DENV as well.Dengue virus (DENV) belongs to the genus Flavivirus in the family Flaviviridae. The four serotypes of DENV (DENV1, DENV2, DENV3, and DENV4) are the leading cause of arboviral diseases in the tropical and subtropical areas (15,17,60). It has been estimated that more than 2.5 billion people in over 100 countries are at risk of infection, and more than 50 million dengue infections occur annually worldwide (15,17,60). While most DENV infections are asymptomatic or result in a self-limited illness, dengue fever (DF), some people may present with the severe and potentially life-threatening diseases dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) (15,17,60).DENV contains a positive-sense, single-stranded RNA genome of about 10.6 kilobases. Flanked by the 5Ј and 3Ј untranslated regions, the single open reading frame encodes a polyprotein precursor, which is cleaved by cellular and viral protease into three structural proteins, the capsid (C), precursor membrane (PrM), and envelope (E), as well as seven nonstructural proteins NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5 (34). The E protein, a glycoprotein of approximately 55 kDa, contains 12 strictly conserved cysteine residues forming six disulfide bridges and is present as a heterodimer with PrM protein before th...

Human antibody responses after dengue virus infection are highly cross-reactive to Zika virus

“…S1B). The fusion loop has been described as a target for broadly cross-reactive antibodies against DENV (21,22) as well as other flaviviruses (23)(24)(25) and could be one of the epitopes targeted by the cross-reactive antibodies described in our study. In addition, despite the amino acid differences between the DENV2 and ZIKV E proteins compared, the two proteins share nearly identical structures (Fig.…”

Specificity, cross-reactivity, and function of antibodies elicited by Zika virus infection

“…ZIKV-immune plasma was also found to cross-react with ZIKV and DENV1-4 E proteins ( fig. S11), possibly because of the abundant EDI/II cross-reactive antibody response (21,(26)(27)(28).…”

Redesign of a cross-reactive antibody to dengue virus with broad-spectrum activity and increased in vivo potency

“…The envelope (E) protein of DV is the major neutralizing target of the humoral immune response (14). Antibodies recognizing the highly conserved fusion loop on E protein demonstrate broad reactivity to all four serotypes; however, their neutralizing potency is limited due to this epitope being largely inaccessible in a mature dengue virion (15). In contrast, antibodies that recognize the "A" β-strand of E protein domain III (EDIII) have been shown to potently neutralize some-but rarely all four-serotypes (SI Appendix, Fig.…”