Viral envelope

[citation needed] In most cases, the known vaccines operate by inducing antibodies that prevent the pathogen from entering cells.

[2] The envelopes are typically derived from portions of the host cell membranes (phospholipids and proteins), but include some viral glycoproteins.

These include the E3 ubiquitin ligases of the membrane-associated RING-CH (MARCH) family, which among other things, inhibits the expression of cell surface proteins implicated in adaptive immunity.

[5] Many enveloped viruses mature by budding at the plasma membrane, which allows them to be discharged from infected cells.

For a very long time, it was thought that the spike proteins, which are necessary for infectivity, were directly incorporated into the viral core through their cytoplasmic domains.

Recent research suggests that while such direct interactions may be what causes the budding of alphaviruses, this may not be the case for retroviruses and negative strand RNA viruses.

These viruses can form bud particles even in the absence of spike proteins by relying only on viral core components.

Therefore, optimal budding and release may be dependent on a coordinated "push-and-pull" action between core and spike, where oligomerization of both components is essential.

TAM receptors, which are potential targets for therapy, are thereby activated by viruses to reduce type I IFN signaling.

[1] The virus wraps its delicate nucleic acid with a protein shell known as the capsid, from the Latin capsa, meaning "box," in order to shield it from this hostile environment.

The nucleic acid inside the capsid is appropriately protected by its modest size and physical difficulty in opening it.

[15] Enveloped viruses possess great adaptability and can change in a short time in order to evade the immune system.