Bone marrow stromal antigen 2 (BST2)

IFN-induced antiviral host restriction factor which effectively blocks the release of diverse mammalian enveloped viruses by straight tethering nascent virions to the membranes of infected cells. Acts as a direct physical tether, holding virions to the cell membrane and connecting virions to each other.

The tethered virions can be internalized by endocytosis and then degraded or they can remain on the surface. In either case, their spread as cell-free virions is restricted.