CD4

Definition

CD4 is a glycoprotein found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells. It plays a crucial role in the immune system by aiding in the activation of T cells through interaction with MHC class II molecules.

5 Must Know Facts For Your Next Test

1. CD4 is essential for the activation of T helper cells which are pivotal in orchestrating the adaptive immune response.
2. The CD4 molecule interacts specifically with MHC class II molecules presented by antigen-presenting cells.
3. HIV targets CD4+ T cells, leading to their depletion and resulting in compromised immune function.
4. CD4 counts are used clinically to monitor the progression of HIV infection and guide treatment decisions.
5. In addition to T helper cells, CD4 is also expressed on other immune cells such as monocytes, macrophages, and dendritic cells.

Review Questions

Related terms

T Helper Cells: A type of T cell that plays an essential role in the immune system by activating other immune cells.

MHC Class II Molecules: Proteins on antigen-presenting cells that present antigens to CD4+ T helper cells.

Antigen-Presenting Cells (APCs):

Cells such as dendritic cells, macrophages, and B lymphocytes that process and present antigens to T lymphocytes.