The human immunodeficiency virus (HIV) causes AIDS (acquired immunodeficiency syndrome) and interferes with the body's ability to fight infection. The HIV infects macrophages and TH cells and upon infection, it inactivates these cells and hence, suppresses the immune system.
The structure of the virus is such that it is enveloped with a viral envelope (consists of a bilipid layer and proteins) inside which two identical molecules of single-stranded RNA molecules and two molecules of reverse transcriptase are present. The reverse transcriptase enzyme generates viral DNA inside the host by using viral RNA as a template.