1. HIV has surface proteins called gp120 that attach to cells with CD4 receptors on their surfaces. CD4 is found on helper T-Cells, and on macrophages of the immune system.
2. The HIV virus binds with the cell, and the soon to be host cell incorporates the virus’s membrane into its own and the viral core enters the host cell. Upon entrance, the virus loses its membrane—allowing it to introduce its RNA into the cytoplasm.
3. Viral enzymes convert the viral RNA into DNA, and the viral enzyme reverse transcriptase copies the RNA into complementary DNA (cDNA). Reverse transcriptase has a high error rate, and frequently mutates the copied DNA—allowing the virus to evolve quickly.
4. The viral RNA is destroyed by another viral enzyme called ribonuclease H, and then reverse transcriptase synthesizes a second DNA strand using the first as a template.
5. The double stranded viral DNA enters the nucleus with the help of viral proteins, and integrase enzymes splice the viral DNA into the cell’s chromosomal DNA. This strand is known as provirus.
6. The synthesis of the viral genome begins with the transcription of this proviral DNA into RNA, which contains the code to produce capsid proteins (and others) needed for viral assembly.
7. In this spliced form, the RNA codes also for the envelope proteins and other auxiliary proteins. These are produced in the rough ER, then moved through the golgi before arriving at the cell surface.
8. Full length viral RNA molecules, along with all other viral components, assemble at the membrane and bud off the cell. It’s not clear how HIV stops the immune response, nor how it causes the destruction of T cells—it ultimately results in the loss of all functional T helper cells in the immune system.