AIDs virus. Coloured scanning electron micrograph of the viruses (blue spots) causing AIDS (Acquired Immune Deficiency Syndrome). They are budding from the plasma membrane of an infected T4 helper" lymphocyte. The virus, designated HIV (Human Immunodeficiency Virus), destroys the T4 lymphocytes, a type of white blood cell which induces other T-cells - "killer" lymphocytes - to fight invaders. Once inside the lymphocyte a single strand of viral RNA is transcribed into DNA & penetrates the nucleus to subvert the cell's DNA, which it uses to replicate viral RNA & generate new viruses. These break out of the lymphocyte, destroying it, and infect other cells."