lentivirus

Lentivirus is a genus of enveloped, single-stranded positive-sense RNA viruses in the family Retroviridae. Members share a characteristic slow replication and long incubation periods. The most studied species are human immunodeficiency viruses HIV-1 and HIV-2, as well as simian immunodeficiency viruses (SIV), equine infectious anemia virus (EIAV), and feline immunodeficiency virus (FIV).

Like other retroviruses, lentiviruses carry two copies of RNA genome and replicate through a DNA intermediate. Upon infection, the viral RNA is reverse-transcribed into DNA and integrated into the host genome, where the provirus is transcribed by host RNA polymerase II. The genome encodes gag, pol, and env genes, and a set of regulatory and accessory genes (for example tat and rev in HIV), which modulate replication and pathogenesis. Enveloped virions display reverse transcriptase, integrase, and protease enzymes; high genetic variability arises from error-prone replication and recombination.

Natural infections in humans lead to acquired immunodeficiency and, with HIV, to AIDS if untreated. Transmission occurs mainly via sexual contact, blood exposure, and vertical transfer from mother to child. In non-human species, lentiviruses cause similar chronic infections. SIV infects many primates; EIAV infects horses; FIV infects cats.

Lentiviral vectors are widely used in molecular biology and gene therapy to deliver transgenes. They can transduce non-dividing cells and integrate into the host genome, enabling long-term expression; vectors are typically replication-deficient and employed under appropriate biosafety containment.

Safety and regulation: research uses adhere to biosafety levels appropriate to the strain and construct; work with replication-competent lentiviruses is restricted; regulatory approvals govern clinical gene therapy applications.