Recent advancements in combination subunit vaccine development

Abstract

Viral structural proteins share a common nature of homotypic interactions that drive viral capsid formation. This natural process has been mimicked in vitro through recombinant technology to generate various virus-like particles (VLPs) and small subviral particles that exhibit similar structural and antigenic properties of their authentic viruses. Therefore, such self-assembled, polyvalent, and highly immunogenic VLPs and small subviral particles are excellent subunit vaccines against individual viruses, such as the VLP vaccines against the hepatitis B virus, human papilloma virus, and hepatitis E virus, which have already been in the markets. In addition, various antigens and epitopes can be fused with VLPs, small subviral particles, or protein polymers, forming chimeric mono-, bi-, or trivalent vaccines. Owing to their easy-production, uninfectiousness, and polyvalence, the recombinant, chimeric vaccines offer a new approach for development of safe, low-cost, and high efficient subunit vaccines against a single or more pathogens or diseases. While the first VLP-based combination vaccine against malaria has been approved for human use, many others are under development with promising future, which are summarized in this commentary.

Hepatitis B Virus (HBV) Subviral Particles as Protective Vaccines and Vaccine Platforms

“…SVPs display an array of antigenic sequences to the innate immune system facilitating the subsequent activation of the adaptive system [8,10,186,187]. The ability to accept foreign inserts into the SVP structure provides the basis for advanced delivery platforms for medically relevant sequences, such as malaria antigens.…”

Bioengineered Polyhydroxyalkanoates as Immobilized Enzyme Scaffolds for Industrial Applications

“…However, VLPs do not contain nucleic acids, and, thus, there is no risk of causing infection (Charlton Hume et al, 2019;Janitzek et al, 2019). The CP subunits can be genetically modified for bioconjugation, enabling molecules of interest to be densely displayed or encapsulated in homogeneous spatial orientation (Tan and Jiang, 2017;Charlton Hume et al, 2019). VLPs have made significant advances in various fields, from vaccinology to industrial uses due to their promising characteristics, including monodispersed particle size distribution, defined geometric surfaces, biosafety, and functional programmability (Mohsen et al, 2017;Janitzek et al, 2019).…”

“…Additionally, the viral capsids are stable over a wide range of environmental conditions, such as temperatures and pHs, which make them suitable for different applications, including industrial biocatalysis (Stanley, 2014;Koch et al, 2015;Brasch et al, 2017;Torbensen et al, 2019). Nevertheless, VLPs are challenging to be abundantly produced at the industrial scale (Mohsen et al, 2017;Tan and Jiang, 2017). A significant drawback of the VLP platform is that the size of the protein attached to, or accommodated within, the particles is limited.…”

Multi-Antigenic Virus-like Particle of SARS CoV-2 produced inSaccharomyces cerevisiaeas a vaccine candidate

“…Amongst different technologies that are being adapted for developing the vaccine candidate, VLPs are known to be a potent technology for increased immunogenicity and there are number of examples of commercial vaccines and candidates under trial as VLPs (3,4). Most of the VLP vaccines utilize a major surface protein to form the VLP (5). A strong B cell response is shown by VLPs even in the absence of adjuvants due to efficient crosslinking with specific receptors on B cells (6,7).…”

“…A strong B cell response is shown by VLPs even in the absence of adjuvants due to efficient crosslinking with specific receptors on B cells (6,7). In developing VLPs as vaccine candidates, one of the significant challenges has been to incorporate multiple surface antigens, express them in a single host and allow self-assembly into a VLP (5).…”