AP BIOLOGY

Detailed explanation-1: -HIV infects and destroys certain white blood cells called CD4+ cells. If too many CD4+ cells are destroyed, the body can no longer defend itself against infection. The last stage of HIV infection is AIDS (acquired immunodeficiency syndrome).

Detailed explanation-2: -HIV binds to the CD4 molecule on the surface of helper T-cells and replicates within them. This results in destruction of CD4+ T-cells and leads to a steady decline in this population of T-cells.

Detailed explanation-3: -HIV attacks a specific type of immune system cell in the body. It’s known as the CD4 helper cell or T cell. When HIV destroys this cell, it becomes harder for the body to fight off other infections.

Detailed explanation-4: -CD4 T lymphocytes (CD4 cells) help coordinate the immune response by stimulating other immune cells, such as macrophages, B lymphocytes (B cells), and CD8 T lymphocytes (CD8 cells), to fight infection. HIV weakens the immune system by destroying CD4 cells.