KEY CONCEPT When the immune system is weakened, the body cannot fight off disease.

HIV targets the immune system. The human immunodeficiency virus (HIV) is a retrovirus. attacks and weakens the immune system is transmitted by mixing infected blood with a bodily fluid

HIV infection leads to AIDS. T cell dead T cell antibody activated B cell HIV reproduces in and destroys T cells. The body cannot replace T cells fast enough. T cells cannot help in immune responses.

AIDS is acquired immune deficiency syndrome. several opportunistic infections very low amount of T cells