Analysis of Individuals from a Dengue-Endemic Region Helps Define the Footprint and Repertoire of Antibodies Targeting Dengue Virus 3 Type-Specific Epitopes

Abstract

The four dengue virus serotypes (DENV1 to 4) cause dengue, a major public health problem worldwide. Individuals exposed to primary DENV infections develop serotype-specific neutralizing antibodies, including strongly neutralizing antibodies targeting quaternary epitopes. To date, no studies have measured the levels and kinetics of serum antibodies directed to such epitopes among populations in regions where dengue is endemic. Here, we use a recombinant DENV4 (rDENV4/3-M14) displaying a major DENV3 type-specific quaternary epitope recognized by human monoclonal antibody 5J7 to measure the proportion, magnitude, and kinetics of DENV3 type-specific neutralizing antibody responses targeting this epitope. Primary DENV3 sera from 30 individuals in a dengue hospital-based study in Nicaragua were studied 3, 6, 12, and 18 months post-infection, alongside samples collected annually 1 to 4 years post-primary DENV3 infection from 10 individuals in a cohort study in Nicaragua. We found substantial individual variation in the proportion of DENV3 type-specific neutralizing antibody titers attributed to the 5J7 epitope (range, 0 to 100%), with the mean significantly increasing from 22.6% to 41.4% from 3 to 18 months. We extended the transplanted DENV3 5J7 epitope on the virion (rDENV4/3-M16), resulting in increased recognition in several individuals, helping define the footprint of the epitope. However, 37% and 13% of the subjects still showed little to no recognition of the 5J7 epitope at 3 and 18 months, respectively, indicating that one or more additional DENV3 type-specific epitopes exist. Overall, this study demonstrates how DENV-immune plasma from populations from areas of endemicity, when coupled with structurally guided recombinant viruses, can help characterize the epitope-specific neutralizing antibody response in natural DENV infections, with direct implications for design and evaluation of dengue vaccines.

Beyond Neutralizing Antibody Levels: The Epitope Specificity of Antibodies Induced by National Institutes of Health Monovalent Dengue Virus Vaccines

“…No appreciable loss of DENV3 neutralization was observed with the DENV3/1 virus, suggesting that this region was not a major target of vaccine-induced DENV3 nAbs. The previously described rDENV4/3, displaying the DENV3 type-specific, strongly neutralizing hMAb 5J7 quaternary structure epitope centered on the hinge region between EDI and EDII [36, 37], was not significantly neutralized by vaccine immune sera, demonstrating that the transplanted epitope was not a major target of type-specific nAbs (Figure 3C and Supplementary Figure 5 C ). We noted a modest gain of DENV3 nAbs in 2 subjects, indicating that the DENV3 vaccine can induce low levels of antibodies that track with this epitope in some people (Figure 3C).…”

“…Our results indicate that other epitopes, yet to be fully described, are the major targets of the DENV3 type-specific response. Indeed, recent studies demonstrate that the 5J7 epitope is not the major target of nAbs in people exposed to primary DENV3 infections as well [36].…”

Expansion and Refinement of Deep Sequence-Coupled Biopanning Technology for Epitope-Specific Antibody Responses in Human Serum

“…These methods have been employed using both mouse and human sera [ 31 , 32 , 33 ]. However, these investigations have focused mostly on the envelope protein, with few studies of antibody profiles of the entire DENV genome [ 34 , 35 , 36 ]. Here, we utilized our DSCB technique and modified it to streamline the approach and make this a more efficient technology for rapid antigen discovery.…”

Adaptive Immunity to Dengue Virus: Slippery Slope or Solid Ground for Rational Vaccine Design?

“…To screen for DENV3-specific neutralising antibody responses, the 5J7 epitope has been transplanted into DENV1 and DENV4 backbones [ 239 , 241 , 242 , 243 ]. It was found that a proportion of neutralising antibodies in post-infection sera bound to the 5J7 epitope, suggesting that specific neutralisation of DENV3 is also mediated by antibodies directed to other sites on the virion [ 242 , 243 ]; indeed, a recent study has identified additional quaternary epitopes on DENV3 [ 244 ]. Interestingly, the chimeric DENV4/3 was not significantly neutralised by rDEN3Δ30 vaccine sera, demonstrating that the 5J7 epitope is not a major target of DENV3-specific neutralising antibodies following vaccination [ 239 ].…”