Alphaviruses, such as western equine encephalitis virus (WEEV), eastern equine encephalitis virus (EEEV), and Venezuelan equine encephalitis virus (VEEV), belong to the category of single-stranded positive-sense RNA-enveloped viruses. The envelope proteins of Alphavirus exhibit icosahedral symmetry, with E2 and E1 glycoproteins forming heterodimers that assemble into 80 trimers. These trimers play a crucial role in receptor interaction and mediating virus-cell membrane fusion. When Alphavirus serves as a vector for gene transfer, the Alphavirus replicon contains cis-acting sequences at both the 5ʹ and 3ʹ ends of the viral genome, as well as all non-structural protein genes. The foreign gene replaces the structural protein ORF, which is then transcribed by the provided helper RNA before being packaged into virus-like particles (VLPs). These replicons enter susceptible host cells and replicate using the viral RNA polymerase complex encoded within the replicons. Alphavirus VLPs closely resemble genuine viruses in appearance and immunogenicity but lack the ability to spread the virus. As a result, they have numerous applications in vaccine research and production.
Fig.1 Structure of Alphavirus VLPs.1
The Alphavirus VLPs from Creative Biolabs provide numerous benefits, including customized gene therapy capabilities and versatile applications in vaccine research and development, gene therapy, and various other fields. Figure 2 illustrates the construction of hACE2 with VEEV replicon particles (VEEV-VRP-hACE2), which is one of the Venezuelan equine encephalitis virus-like particles (VEEVLPs), composed of the VEEV-hACE2 replicon along with two helper RNAs, each expressing the structural protein separately. To generate the VEEVLPs, the hACE2 gene, fused with an S tag sequence, was inserted into a VEEV-TC83 infectious clone, replacing the natural viral capsid structural protein. The two helper RNAs had the VEEV genome, covering most of the nsP4 gene, removed, and a TAA stop codon was introduced at the 3' terminus of the nsP3 gene. Capsid and envelope genes were inserted and expressed independently.
Fig.2 Schematic illustration of VEEV-hACE2 replicon and helper RNA genomes and transduction of host cells with VEEVLPs.2
Creative Biolabs is dedicated to delivering top-notch Alphavirus VLP services worldwide. These VLPs are generated using two distinct expression systems: one based on the yeast Pichia pastoris and the other utilizing baculovirus (BEVS). We offer tailored services encompassing recombinant plasmid packaging for Alphavirus VLPs, along with purification and titer determination. Moreover, we provide a comprehensive approach that involves evaluating VLP protein expression and synthesis through western blotting, immunofluorescence indirect (IFI), and electron microscopy techniques in vitro, and conduct immunogenicity studies of Alphavirus VLPs in vivo upon request. For detailed information, please reach out to us and request a quote. We guarantee a response within 24 hours and will collaborate with you to devise the optimal strategy for your project.
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