Enveloped Virus-Like Particle (eVLP)

Overview of VLPs

Virus-like particles (VLPs) are protein particles self-assembled by a single or multiple viral structural proteins and are similar to natural virus capsids but lack the genetic material and, therefore not infectious. VLPs can be produced in a variety of systems, including bacteria, insects, plants, and mammals. Taking advantage of the hollow structural characteristics of VLP, exogenous cargo can be packaged in its inner cavity, and then through targeted modification of the VLP surface, efficient delivery of therapeutic drugs can be achieved. Depending on whether they are enveloped or not, VLPs can be subdivided into enveloped VLPs (eVLPs) and non-enveloped VLPs, as shown in Fig.1. Non-enveloped VLPs are generally simple in structure, consisting of a single or multiple structural protein(s) of a specific virus, whereas eVLPs have a complicated structure that includes both viral and host membrane components. eVLPs present the following advantages over non-enveloped VLPs:

• Higher delivery efficiency
  eVLP can enter cells through membrane fusion, which benefits the cytoplasmic release and efficient mRNA translation.
• More immunogenic
  The envelope can help the immune system recognize and attack VLPs. This can boost the vaccine's immunogenicity and stimulate the immune system's reaction, enhancing the vaccine's efficacy.
• More stable
  The envelope provides an additional layer of protection, making eVLPs more stable in the external environment and able to maintain their integrity and activity for longer.

Fig.1 Different types of VLPs for antigen presentation and cargo delivery.¹

Applications of eVLPs

eVLPs are also classified as single-layer, double-layer, and multi-layer internal structures that exist beneath the lipid membrane, as shown in Fig.2. eVLPs acquire their lipid membrane from the cell in which they are expressed during VLP assembly and budding. Typically, the self-assembly of eVLPs involves two steps: forming an internal protein and then the acquisition of the membrane. The assembly and ultimate release from the cell of eVLPs may be dependent on internal viral structural proteins, envelope glycoproteins. As a carrier for delivering mRNA, eVLP has a wide range of application prospects, including:

• Vaccine delivery
  Enveloped VLPs can be designed to be used as vaccine carriers to load specific mRNA into VLPs for vaccine delivery. This method can make the mRNA vaccine more stable, and through the immunogenicity and targeting of VLP, it can enhance the immune system's response to the vaccine and improve the effectiveness of the vaccine.
• Gene therapy
  Enveloped VLPs can be used as effective carriers for gene therapy to deliver therapeutic mRNA to specific cells or tissues. Through the protective effect of the envelope and enhanced intracellular delivery, the stability and effectiveness of therapeutic mRNA can be improved, thereby enhancing the effect of gene therapy.
• Cancer treatment
  Enveloped VLPs can be designed for cancer treatment to deliver therapeutic mRNA into tumor cells for inhibiting tumor growth or inducing apoptosis. By enhancing the targeting of VLPs to tumor cells, the delivery efficiency of therapeutic mRNA in tumor tissues can be improved, thereby enhancing the therapeutic effect.

Fig.2 Classification of various enveloped VLP structures.²

SERVICES

Creative Biolabs is committed to offering various types of eVLP to deliver proteins, tRNAs, rRNAs, and mRNAs, including Lentivirus-Like Particles (LVLPs), Murine Leukaemia Virus-Like Particles (MLVPs), Venezuelan Equine Encephalitis Virus-Like Particles (VEEVLPs), and Mammalian Retrovirus-Like Particles (PEG10-VLPs). Please contact us for more detailed information.

References

1. Qian, Ciying, et al. "Recent progress on the versatility of virus-like particles." Vaccines 8.1 (2020): 139.
2. Nooraei, Saghi, et al. "Virus-like particles: Preparation, immunogenicity and their roles as nanovaccines and drug nanocarriers." Journal of nanobiotechnology 19.1 (2021): 1-27.