VLPs are multi-protein structures, which mimic the organization and conformation of authentic native viruses, but lack the viral genome, and may produce safer and cheaper vaccine candidates. If the specific native viral proteins with immunosuppressive function are excluded from VLPs, the efficacy of these particles can be significantly enhanced. Compared with single protein or peptide, VLPs present more similar conformational epitopes to the original virus. Therefore, antibody reactivity or immune system response is expected to be significantly improved. Due to their highly repetitive surfaces, VLPs are able to induce strong B cell responses without adjuvants by effectively crosslinking specific receptors on B cells. Studies have shown that VLP vaccines can stimulate humoral and cellular immune responses, thus providing effective antiviral protection.
Virus-like Particle Based Vaccine for SARS-CoV-2
CoV virions are roughly spherical with an average diameter between 50 and 200 nm. CoVs are composed of four structural proteins: spike protein, envelope protein, membrane protein and nucleocapsid protein. In the study of SARS-VLPs, it was found that SARS-VLPs produced by baculovirus expression system could produce strong IgG and secretory IgA response by mucosal or systemic immunity. In addition, SARS-VLPs can activate dendritic cells (DCs) and induce cellular immune response.