Virus-Like Particles (VLPs)

Characterize Adeno-associated virus (AAV) with Automated Classification

Adeno-associated virus (AAV) is a well-established platform for gene delivery. It is crucial to ensure that AAV formulations are free from impurities that can compromise the efficacy, safety, and immunogenicity of the product. One such impurity is the presence of empty capsids or capsids with incomplete DNA payloads. 

Cryo-TEM imaging combined with quantitative image analysis tools can be used to directly assess the composition of AAV formulations. Automated particle classification enables precise characterization of empty, partially full, and full capsids. Simultaneously, it is possible to visualize integrity, impurities, and the level of aggregation. Cryo-TEM is the ultimate tool to evaluate combined CQAs; for example, it can be used to assess whether it is empty or full capsids that are more prone to aggregation.

Furthermore, cryo-TEM imaging can be used to obtain 2D class averages and create high resolution 3D reconstructions of AAV particles. This can help identify potential post-translational modifications on AAV capsids, decipher the structural impact of mutations on capsid structure, and help understand the molecular basis of receptor bound AAV or epitope mapping.

Visualize Human papillomavirus (HPV)

Human papillomavirus (HPV) is the key component in vaccines such as Gardasil®¹. Cryo-TEM imaging provides excellent visualization to directly determine morphological characteristics of VLP vaccine intermediates such as HPV, including uniformity, shape, particle integrity, size distribution analysis, and level of aggregation. 

By leveraging Cryo-TEM imaging, scientists can gain valuable insights into batch-to-batch variability, scale-up processes, and process development changes. These insights are vital for understanding and optimizing the production of the final drug formulation.

Cryo-TEM can also provide a 3D reconstruction of the particle’s structure, which is achieved by averaging particles of the same morphology and conformation using a single particle analysis workflow.

Download the whitepaper to learn more about NIS’s work on Gardasil®.

1. Qinjian Zhao, Clinton S Potter, Bridget Carragher, Gabriel Lander, Jaime Sworen, Victoria Towne, Dicky Abraham, Paul Duncan, Michael W Washabaugh & Robert D Sitrin (2014) Characterization of virus-like particles in GARDASIL® by cryo transmission electron microscopy, Human Vaccines & Immunotherapeutics, 10:3, 734-739, DOI: 10.4161/hv.27316

Learn About Lentivirus

Cryo-TEM imaging studies offer valuable insights for the assessment of Lentivirus particle morphology. This advanced imaging technique enables researchers to analyze various structural aspects, including size, shape, uniformity, and integrity of the particles. Further, Cryo-TEM allows for the visualization of important characteristics such as maturation state, surface protein morphology and level of surface protein decoration, while also allowing the detection of impurities present in each sample lot.

For a deeper understanding of the structural features, such as maturation state, capsid morphology, packaged genome, and details of the surface proteins, cryo-electron tomography can be performed on a formulation containing heterogeneous populations of particles.