envelopevirioner

Envelopevirioner is a rarely used term that, in practice, refers to a virion that possesses a lipid envelope surrounding its nucleocapsid. The standard term in virology is enveloped virion. The envelope is a lipid bilayer derived from the host cell membrane and is embedded with viral glycoproteins that mediate attachment and entry into susceptible cells. A protein matrix or tegument layer often lies beneath the envelope and helps organize viral components during infection.

Enveloped virions are formed when the nucleocapsid buds through a cellular membrane, such as the plasma membrane or internal membranes of the endoplasmic reticulum–Golgi network. Their genomes can be either DNA or RNA, single- or double-stranded, and replication strategies vary across virus families. The envelope and its glycoproteins are central to host range and tissue tropism.

Compared with nonenveloped virions, enveloped virions are generally more fragile outside the host, rendering them more sensitive to desiccation, heat, detergents, and solvent exposure. This influences transmission modes, which commonly include close contact, respiratory droplets, bodily fluids, or sexual contact, depending on the virus. The envelope is also a major target for the immune response and for vaccines and antivirals that aim to block entry.

Examples of enveloped virions include influenza A virus, HIV-1, SARS-CoV-2, herpesviruses, and many flaviviruses. The envelope is a key factor in pathogenesis and in the development of countermeasures. Note that envelopevirioner as a term is nonstandard; enveloped virion is the preferred expression.