A Nanoparticle-Based Hepatitis C Virus Vaccine With Enhanced Potency.

Area of Science:

• Virology
• Immunology
• Vaccine Development

Background:

• Chronic hepatitis C virus (HCV) infection, fibrosis, and hepatocarcinoma pose significant public health challenges.
• Existing direct-acting antivirals necessitate complementary preventive strategies, such as vaccines.
• Previous research demonstrated that a soluble E2 (sE2) subunit vaccine could induce broadly neutralizing antibodies against HCV.

Purpose of the Study:

• To enhance the immunogenicity of the sE2 protein for a more effective HCV vaccine.
• To design and produce a novel fusion protein, sE2-ferritin, for nanoparticle assembly.
• To evaluate the conformational integrity, binding affinities, and immunogenicity of the sE2-ferritin nanoparticle.

Main Methods:

• A fusion protein (sE2-ferritin) was constructed, combining sE2 with a ferritin unit.
• The fusion protein was produced in Drosophila S2 cells, leading to self-assembly into nanoparticles.
• The sE2 moiety's conformation and binding affinities to antibodies, receptors, and patient serum were assessed.
• Immunogenicity was evaluated in mouse models following immunization with sE2-ferritin compared to unfused sE2.

Main Results:

• The sE2-ferritin nanoparticle displayed the sE2 moiety with near-natural conformation.
• The nanoparticle-displayed sE2 exhibited enhanced binding affinities to neutralizing antibodies, receptors, and patient serum compared to unfused sE2.
• Mouse immunization studies revealed that sE2-ferritin was more potent in inducing broadly neutralizing antibodies against HCV than sE2.
• The sE2-ferritin nanoparticle demonstrated superior immunogenicity in eliciting anti-HCV neutralizing antibodies.

Conclusions:

• The sE2-ferritin nanoparticle represents a promising vaccine candidate for hepatitis C virus.
• This nanoparticle vaccine demonstrates enhanced immunogenicity and potential for inducing broadly neutralizing antibodies.
• sE2-ferritin offers a superior alternative to previous sE2-based vaccines, advancing the possibility of HCV control.