The Effect of HIV on Humans
HIV is such a deadly virus, and is so difficult to fight off, because it specifically targets cells in the immune system. The receptor for HIV is a protein called CD4, mostly found on helper T cells (see Chapter 15). In the progression of AIDS, the CD4 bearing cells are killed and the ability of the immune system to fight off other diseases and opportunistic infections is drastically reduced. Individuals do not die from AIDS, but rather from infections that can normally be fought off by a healthy immune system.