A type of T lymphocyte that helps coordinate immune responses and is a major target of HIV infection.
CD4 T lymphocytes, also called CD4 T cells or helper T cells, help other immune cells respond appropriately to infectious agents. They recognize signals from immune cells and help coordinate activities such as antibody production and the activation of other immune cells.
HIV can enter and infect CD4 T lymphocytes. Over time, untreated HIV infection can reduce the number and function of these cells, weakening immune defenses. CD4 count is therefore an important measure of immune function in people with HIV.
QUICK FACT
CD4 is a protein on the surface of certain immune cells as well as the name commonly used for the cells that carry it.
COMMONLY CONFUSED WITH
CD4 count: A CD4 T lymphocyte is a type of immune cell; the CD4 count is a measurement of how many CD4 cells are present in a given volume of blood.
SEE ALSO