pseudotyped

Pseudotyped refers to viral particles or virus-like vectors that bear envelope glycoproteins from one virus on the core of another, enabling entry properties of the donor envelope while preserving the genetic material of the backbone. This approach, known as pseudotyping, creates pseudoviruses or pseudotyped vectors that are often replication-defective, allowing researchers to study entry mechanisms or deliver genes under safer conditions than with wild-type pathogens.

Mechanism and construction: A heterologous envelope protein is produced in producer cells along with a separate genome and structural proteins of the backbone. The resulting particles acquire the donor envelope, which determines cell tropism and receptor usage. Pseudotyped vectors commonly use lentiviral or retroviral backbones, sometimes vesicular stomatitis virus (VSV) or other envelopes such as influenza HA or coronavirus spike proteins. Particles are typically produced by transient transfection and are quantified by reporter gene expression in target cells.

Applications: Pseudotyping is used to analyze entry pathways, identify receptors, evaluate neutralizing antibodies, and test antiviral compounds. It also enables gene delivery in research and, with appropriate safety features, in preclinical gene therapy.

Limitations and considerations: The envelope swap can alter particle assembly, stability, and tropism compared with authentic viruses. Results may not fully reflect natural infection, and use requires appropriate biosafety and ethical approvals. Potential risks include recombination and unintended host range expansion, though replication competency is usually restricted.

See also: pseudovirus, viral vector, gene delivery, viral entry.