Hemachatus haemachatus

Helper cell

A helper cell or CD4+ T cell is a type of T cell that plays an integral role in the immune system, particularly in the adaptive immune system. These cells have a T-cell receptor on their cell surface, but their defining characteristic is the presence of the CD4 glycoprotein, which enables the cell to interact with antigen-presenting cells.

Function

The primary function of helper cells is to regulate immune responses. They do this by recognizing fragments of antigens on the surface of antigen-presenting cells and responding by producing cytokines, which are chemical messengers that help to stimulate the appropriate immune response.

There are several types of helper cells, including Th1, Th2, Th17, and Tfh cells, each of which produces different types of cytokines and stimulates different types of immune responses. For example, Th1 cells are involved in cell-mediated immunity, while Th2 cells are involved in humoral immunity.

Role in disease

Helper cells are crucial for a healthy immune system, but they can also be involved in disease. For example, in HIV infection, the virus primarily targets helper cells, leading to a progressive decline in their numbers and eventually to AIDS.

See also

• T cell
• Immune system
• Antigen-presenting cell
• Cytokine
• HIV
• AIDS