HEV VLP 

Hepatitis E virus-like particles (HEV VLPs) are non-infectious nanoparticles that mimic the structural and antigenic properties of the Hepatitis E virus (HEV) without containing its RNA genome. HEV, a non-enveloped, single-stranded RNA virus, is a leading cause of acute viral hepatitis globally. HEV VLPs have been extensively explored for vaccine development, diagnostics, and immunological studies due to their safety and ability to elicit strong immune responses.

Structure of HEV VLPs

HEV VLPs are primarily composed of the capsid protein derived from the open reading frame 2 (ORF2) of the HEV genome:

• Capsid Protein (ORF2): Self-assembles into icosahedral VLPs resembling the native HEV virion. The truncated form of the ORF2 protein (e.g., amino acids 112–608 or 112–660) is commonly used for VLP production to enhance solubility and assembly efficiency.
• Optional Surface Modifications: HEV VLPs can be engineered to display additional antigens or epitopes for multivalent vaccine applications.

Production Systems

HEV VLPs are produced using recombinant expression systems tailored to scalability and functionality:

• Yeast Systems (e.g., Pichia pastoris): Commonly used for producing HEV VLPs, especially for commercial vaccines (e.g., Hecolin).
• Insect Cells: Employ the baculovirus expression system to produce high yields of functional VLPs.
• Mammalian Cells: Used for advanced post-translational modifications when needed.

Applications

• Vaccines
  • Prophylactic Vaccines: HEV VLP-based vaccines, such as Hecolin (commercially available in China), protect against HEV infection by inducing strong neutralizing antibody responses.
  • Multivalent Vaccines: HEV VLPs can be engineered to include antigens from other hepatitis viruses or pathogens for broader protection.
• Diagnostics
  • HEV VLPs are used as antigens in serological assays (e.g., ELISA) to detect HEV-specific antibodies (IgM/IgG) or to assess past exposure and immunity.
• Immunological Research
  • Serve as tools to study HEV-host interactions and immune mechanisms, including neutralization and T-cell responses.

Hepatitis E virus-like particles represent a highly effective and safe platform for vaccines, diagnostics, and immunological research. With ongoing advancements, HEV VLPs hold significant potential for addressing the global burden of hepatitis E and for broader applications in multivalent vaccine development and therapeutic delivery systems.