Lentivirus is a genus of retroviruses that cause chronic and deadly diseases characterized by long incubation periods, in humans and other mammalian species.

Lentiviruses are distributed worldwide, and are known to be hosted in apes, cows, goats, horses, cats, and sheep as well as several other mammals.

[1] Five serogroups of lentiviruses are recognized, reflecting the vertebrate hosts with which they are associated (primates, sheep and goats, horses, domestic cats, and cattle).

They may also have additional accessory genes depending on the virus (e.g., for HIV-1: vif, vpr, vpu, nef) whose products are involved in regulation of synthesis and processing viral RNA and other replicative functions.

Glycosylation seems to play a structural role in the concealment and variation of antigenic sites necessary for the host to mount an immune system response.

Antigen determinants that possess type-specific reactivity and are involved in antibody mediated neutralization are found on the glycoproteins.

Large-scale collaborative efforts are underway to use lentiviruses to block the expression of a specific gene using RNA interference technology in high-throughput formats.

Lentiviruses have also been successfully used for transduction of diabetic mice with the gene encoding PDGF (platelet-derived growth factor),[12] a therapy being considered for use in humans.

[13] These treatments, like most current gene therapy experiments, show promise but are yet to be established as safe and effective in controlled human studies.