Ultrastructural features of the AIDS virus (HIV) and its morphogenesis

Abstract

HIV particles were usually seen on the surface of established lymphoid cells derived from AIDS patients or on CEM cells infected with HIV, and sometimes in cytoplasmic vacuoles. The virus particles were formed by a budding process from the plasma membrane of an infected cell. The budding particles were of a doughnut form. Various profiles of virus particles were seen extracellularly: type 1 had a bar‐shaped, electron‐dense core, type 2 had a central and type 3 an eccentric electron‐dense round core, type 4 was doughnut‐shaped, and type 5 had a layered core. However, projection patterns of the AIDS virus model suggested that type 1, 2 and 3 particles are similar. Therefore, the AIDS virus may be one of three main types: with or without a dense core, and with a layered core. It is thought that a particle with a layered core and a doughnut‐type particle may be immature viruses.