T-4 cell

T-4 cell A T cell that expresses the CD4 transmembrane glycoprotein (CD4+ T cell). T-4 cells are active in the body’s immune response, helping to turn on this system when it is challenged by an infection or by foreign matter in the body. HIV attacks T-4 cells, knocking out the body’s ability to defend itself against infections. T-helper cells fall into two main classes: those that activate other T cells to achieve cellular inflammatory responses; and those that drive B cells to produce antibodies in the humoral immune response. These two classes of response are generally incompatible with one another and require coordination by substances called cytokines to promote one response while dampening the other. Also known as T-helper cell and TH cell. See also CD4; T cell.