HIV invades helper T cells and uses them to reproduce. This is shown inFigure21.7. Then
the virus kills the helper T cells. As the number of viruses in the blood rises, the number
of helper T cells falls. Without helper T cells, the immune system is unable to protect the
body. As a result, the infected person cannot fight infections and other diseases.
Figure 21.7: In this picture, the large structure on the left is a helper T cell. It is infected
with HIV. The many small circles on the right are new HIV viruses being shed by the T cell.
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Medications can slow down the increase of viruses in the blood. However, the medications
cannot rid the body of all the viruses. At present, there is no cure for HIV infection.