Alpha Lifetech Inc. focuses on recombinant protein expression in different Biosystems for many years, including prokaryotic and eukaryotic organisms, as well as the development of novel high-potency recombinant proteins.

Recombinant Protein Expression Services – Virus-like Particle (VLP) Expression Service

Virus-like particles (VLPs) are a highly effective type of subunit vaccine that mimic the overall structure of virus particles without the requirement of containing infectious genetic material. Capsid proteins of many types of viruses can assemble into virus-like particles (VLPs). VLPs can be recognized readily by the immune system and present viral antigens in a more authentic conformation than other subunit vaccines, such as recombinant subunit proteins. In order to enhance the immunogenicity of VLPs, these antigens often contain main structure proteins such as poliovirus-like particle that contains VP1, VP2, VP3 and VP4 subunit from wild-type of virus without genetic materials.

Alpha Lifetech Inc. has created a powerful platform to express recombinant proteins including membrane proteins and virus-like particles based on cell or cell-free expression systems. For example, we successfully expressed Sabin poliovirus-like particle which contains four major structure proteins in a cell-free system.

Fig 1 Negative Staining of Poliovirus-like Particle.

Poliovirus-like particle (type1/2/3) that contains VP1, VP2, VP3 and VP4 subunits from wild-type of virus but without genetic materials, illustrated as shown figure 2, could initiate host cells strongly immune reactions through APC signal pathways.

Fig 2 Virus-like particle of Poliovirus type1/2/3 Expressed in mammalian-based lysates and purified by Molecular Chromatography

All vaccinated rats developed neutralizing antibodies and when challenged with virulent virus on day 42, were protected from disease. Furthermore, rat potency assay shows that the neutralizing antibody titres of three different types (P1, P2 and P3) of poliovirus-like particles (Poliovirus VLPs) reach 1: 1024, 1: 256 and 1: 512, separately when these animals are injected with 2.5 μg Poliovirus VLPs/each rat/ after day 28.

Alpha Lifetech Inc. also provides related services like virus-like particles including thermal stability, virus integrality, virulence test (transfection ability), chimeric plant virus expression system based on VLPs and develops a final product of vaccine containing adjuvants.