Epitope resurfacing on dengue virus-like particle vaccine preparation to induce broad neutralizing antibody

Abstract

Dengue fever is caused by four different serotypes of dengue virus (DENV) which is the leading cause of worldwide arboviral diseases in humans. Virus-like particles (VLPs) containing flavivirus prM/E proteins have been demonstrated to be a potential vaccine candidate; however, the structure of dengue VLP is poorly understood. Herein VLP derived from DENV serotype-2 were engineered becoming highly matured (mD2VLP) and showed variable size distribution with diameter of ~31 nm forming the major population under cryo-electron microscopy examination. Furthermore, mD2VLP particles of 31 nm diameter possess a T = 1 icosahedral symmetry with a groove located within the E-protein dimers near the 2-fold vertices that exposed highly overlapping, cryptic neutralizing epitopes. Mice vaccinated with mD2VLP generated higher cross-reactive (CR) neutralization antibodies (NtAbs) and were fully protected against all 4 serotypes of DENV. Our results highlight the potential of ‘epitope-resurfaced’ mature-form D2VLPs in inducing quaternary structure-recognizing broad CR NtAbs to guide future dengue vaccine design.

Mosquito Cell-Derived Japanese Encephalitis Virus-Like Particles Induce Specific Humoral and Cellular Immune Responses in Mice

“…The maturity of flavivirus VLPs affects epitope display and antigenicity. The 6B6C-1 Mab of the conformational-dependent Mabs performs the specific ability to bind mature flavivirus VLPs [55]. In dot blot analysis ( Figure 3) and MAC-ELISA assays (Figure 5), the specific binding of JEV human sera and two conformation-sensitive mAbs (6B6C and D56-3) to VLPs demonstrated that the secreted JEV VLPs maintained virion-like epitopes with maturity.…”

“…The process of flavivirus maturation is regulated by the proteolytic cleavage of the precursor membrane protein (prM) [54]. The maturity of VLPs affects the display and antigenicity of epitopes [55]. The conformationally dependent Mab 6B6C-1 specifically binds mature flavivirus VLPs, such that dot blot analysis results obtained using 6B6C-1 Mab ( Figures 3A and 4A) indicated that the JEV VLPs were mature.…”

Does structurally-mature dengue virion matter in vaccine preparation in post-Dengvaxia era?

“…77 More recently, a study demonstrated that a highly mature DENV-2 strain 16681-derived virus-like particles (mD2VLP) produced from mammalian COS-1 cells can generate higher cross-reactive NtAbs, and mice receiving passively transferred antibodies from immunized mice were protected against all four serotypes of DENV. 32 Further, cryo-EM reconstruction showed that these mD2VLP particles possess a T = 1 icosahedral symmetry with a groove located within the E protein dimers near the 2-fold vertices and exposed highly overlapping, cryptic neutralizing epitopes. 32 The results highlighted the potential of these "epitoperesurfaced" mature-form D2VLPs in inducing quaternary structure-recognizing broadly cross-reactive NtAbs.…”

“…32 Further, cryo-EM reconstruction showed that these mD2VLP particles possess a T = 1 icosahedral symmetry with a groove located within the E protein dimers near the 2-fold vertices and exposed highly overlapping, cryptic neutralizing epitopes. 32 The results highlighted the potential of these "epitoperesurfaced" mature-form D2VLPs in inducing quaternary structure-recognizing broadly cross-reactive NtAbs. Covalently locked E protein dimers through cross-linking of the inter-subunit disulfide bonds is another dengue vaccine design that can also present resurfaced conformational EDE epitopes and with reduced exposure of the immunodominant FLE.…”

“…The computational prediction also indicated the presence of sub-optimal amino acid motif surrounding the pr and M junction region cleavable by furinlike protease. 32,33 For these reasons, dengue virions released from infected cells consist of different degrees of maturation, and can be characterized as heterogeneous and mosaic particles with pr portion of prM proteins that are uncleaved (immature DENV), incompletely cleaved (partially mature DENV) or completely cleaved (mature DENV). 34,35 The exact composition of these structurally heterogeneous DENV virions in human and mosquito during natural infection is unknown, although a recent publication suggested that it could be mostly mature in humans.…”