HIV is an enveloped retrovirus. Each virus particle contains two copies of an RNA genome. The virus also has a number of enzymes: reverse transcriptase, integrase and viral protease. But, once I also find that HIV also belongs to lentiviruses. I am not very familiar with the relationship between retrovirus and lentiviruses. And does here have somebody know why HIV is a kind of lentivirus?
In Latin, lente means slow, so lentiviruses are retroviruses that are characterized by long periods of latency.
lentivirus A group of retroviruses that include human immunodeficiency virus, HIV-1. They cause disease after a long incubation period.
latency A state in which a virus infects a cell but does not replicate.
-Janeway's Immunobiolgy, 8th Edition, Kenneth M. Murphy
HIV-1 is characterized by long incubation periods. It can often take months before the virus is detectable on HIV tests.
It is also known that HIV reservoirs will exist in a patient, such that even if they have undetectable viral loads when on Antiretroviral Therapy, once they come off of the treatment, they will begin to produce virons again. The likely reason for that is that the immune cells that they infect can be very long lived, and as the viral genome has been incorporated into the host cells genomic DNA, it is incredibly stable. It will stay dormant for years until it is able to replicate again.
There're 6 genuses under the family"orthoretrovirinae": alpharetrovirus, betaretrovirus, gammaretrovirus, deltaretrovirus, epsilonretrovirus and lentivirus. So the question came down to the differences between lentiviruses and other retroviruses. Here are some major differences:
Lentiviruses have a cone shape capsid while other retroviruses have a icosahedral capsid.
Retroviruses share 3 common genes: gag, pol and env. While lentiviruses share 2 additional genes: tat and rev.
Lentiviruses have an overlap between gag and pol, and a gap between pol and env. While retroviruses have no overlap between gag and pol and an overlap between pol and env.
Retroviruses can only infect mitosis cells while lentiviruses are capable of infecting non dividing cells.
Pathogenesis of retroviruses and lentiviruses are also very different.