Infectious Cycle Stages
- The human immunodeficiency virus (HIV) enters the body through a break in the skin barrier.
- Protein antibodies are produced initially against the newly entered HIV proteins (antigens).
- The AIDS HIV targets certain white cells (T4) because T4 cells have a specific protein, CD4, which fits the shape of the HIV.
- The AIDS HIV enters T4 cells by a cellular infolding called endocytosis.
- Inside T4 cells, AIDS HIV sheds its protein coat and releases two strands of RNA and a reverse transcriptase enzyme.
- The HIV causes the cell to synthesize a double strand of DNA complementary to the viral RNA.
- The newly transcribed viral DNA inserts itself into the T4 cell's DNA.
- The AIDS HIV may remain inactive (latent ) for many years without producing any virus proteins - average is 8 years.
- The activated HIV DNA copy takes over the host T4 cell's ribosomal protein factories and begins making more HIV.
- Activated HIV produces more virus particles that may be budded off from the T4 cells to begin infecting other T4 cells.
- As the AIDS HIV infects more and more T4 blood cells, the cells' ability to produce more antibodies decreases - even for usually harmless infectious proteins.
- Opportunistic infections such as the cancer Kaposi's sarcoma, and usually harmless lung infections, such as Pneumocystis crenii, invade the body.
- T4 white blood cells may burst (lyse) releasing even greater numbers of HIV to invade other cells.
- Once cells begin producing the virus, the body defenses decline at a rapid rate, generally producing death in as little as 2 years from diagnosis.
- AZT is a drug used to prolong the life of an AIDS patient. AZT will be used by the body instead of thymadine in the replication of DNA, AZT prevents DNA replication.
- There is no known cure for AIDS.