Chimeric Hepatitis B core antigen virus-like particles displaying the envelope domain III of dengue virus type 2.
BACKGROUND
Dengue is a global public health problem for which no drug or vaccine is available. Currently, there is increasing interest in developing non-replicating dengue vaccines based on a discrete antigenic domain of the major structural protein of dengue viruses (DENVs), known as envelope domain III (EDIII). The use of bio-nanoparticles consisting of recombinant viral structural polypeptides, better known as virus-like particles (VLPs), has emerged as a potential platform technology for vaccine development. This work explores the feasibility of developing nanoparticles based on E. coli-expressed recombinant Hepatitis B virus core antigen (HBcAg) designed to display EDIII moiety of DENV on the surface.


RESULTS
We designed a synthetic gene construct encoding HBcAg containing an EDIII insert in its c/e1 loop. The fusion antigen HBcAg-EDIII-2 was expressed in E. coli, purified to near homogeneity using Ni+2 affinity chromatography and demonstrated to assemble into discrete 35-40 nm VLPs by electron microscopy. Competitive ELISA analyses showed that the EDIII-2 moieties of the VLPs are accessible to anti-EDIII-2-specific monoclonal and polyclonal antibodies, suggesting that they are surface-displayed. The VLPs were highly immunogenic eliciting high titer anti-EDIII-2 antibodies that were able to recognize, bind and neutralize infectious DENV based on ELISA, immunofluorescence and virus-neutralization assays.


CONCLUSIONS
This work demonstrates that HBcAg-derived nanoparticles can serve as a useful platform for the display of DENV EDIII. The EDIII-displaying nanoparticles may have potential applications in diagnostics/vaccines for dengue.
Recombinant Gene Products Group, International Centre for Genetic Engineering & Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
Upasana
U
Arora
Poornima
P
Tyagi
Sathyamangalam
S
Swaminathan
Navin
N
Khanna
D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D003715:Dengue / Q000276:immunology / Q000517:prevention & control*; D053059:Dengue Vaccines / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D003716:Dengue Virus / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006512:Hepatitis B Core Antigens / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D014611:Vaccination; D058425:Vaccines, Virus-Like Particle / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification
D000914:Antibodies, Viral; D053059:Dengue Vaccines; D006512:Hepatitis B Core Antigens; D058425:Vaccines, Virus-Like Particle; D014759:Viral Envelope Proteins