Abstract

Molecular mechanisms by which human lentiviruses, such as human immunodeficiency virus type 1 (HIV-1), are sexually transmitted have yet to be fully elucidated. It is now demonstrated that endogenous reverse transcription of lentiviruses can occur within the intact virion, before infection of target cells. This is a biochemically active process and is altered by the microenvironment to which HIV-1 virions are subjected. Stimulation of endogenous reverse transcription within virion particles, without nonphysiological permeabilization, has been called natural endogenous reverse transcription (NERT). This molecular mechanism has been shown to augment HIV-1 infection in initially quiescent peripheral blood mononuclear cells (PBMCs) as well as nonproliferating macrophages. As such, this process may be important in augmenting the sexual transmission of HIV-1, as genital secretions have been shown to stimulate NERT within HIV-1 virion particles. Further studies are planned to elucidate fully this initial molecular mechanism, which may be critical in understanding the sexual transmission of HIV-1 and therefore the spread of the AIDS pandemic.