Infectious Cycle Stages

1. The human immunodeficiency virus (HIV) enters the body through a break in the skin barrier.

2. Protein antibodies are produced initially against the newly entered HIV proteins (antigens).

3. The AIDS HIV targets certain white cells (T4) because T4 cells have a specific protein, CD4, which fits the shape of the HIV.

4. The AIDS HIV enters T4 cells by a cellular infolding called endocytosis.

5. Inside T4 cells, AIDS HIV sheds its protein coat and releases two strands of RNA and a reverse transcriptase enzyme.

6. The HIV causes the cell to synthesize a double strand of DNA complementary to the viral RNA.

7. The newly transcribed viral DNA inserts itself into the T4 cell's DNA.

8. The AIDS HIV may remain inactive (latent ) for many years without producing any virus proteins - average is 8 years.

9. The activated HIV DNA copy takes over the host T4 cell's ribosomal protein factories and begins making more HIV.

10. Activated HIV produces more virus particles that may be budded off from the T4 cells to begin infecting other T4 cells.

11. 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.

12. Opportunistic infections such as the cancer Kaposi's sarcoma, and usually harmless lung infections, such as Pneumocystis crenii, invade the body.

13. T4 white blood cells may burst (lyse) releasing even greater numbers of HIV to invade other cells.

14. 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.

15. 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.

16. There is no known cure for AIDS.

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