LAG3

CD4+ T-helper cells (Th) are the white blood lymphocytes expressing surface glycoprotein antigen CD4. These T-helper cells play an important role in the adaptive immune system by releasing T cell cytokines that help other immune cells to suppress or regulate immune responses. CD4+ T-helper lymphocytes can be divided into two types (Th1 and Th2) based on their cytokine secretion. Th1 cells are involved in cell-mediated immune response to intracellular pathogens and delayed-type hypersensitivity reactions.

The LAG3 protein belongs to the Ig superfamily and contains 4 extracellular Ig-like domains (D1-D4). This molecule plays an key role in the immune response through negative regulation of T-cell proliferation, function, and homeostasis. It is required for maximum natural and induced regulatory T-cell function. LAG3 is closely related to the T-cell co-receptor CD4, and like CD4, binds to MHC class II molecules - but with a significantly higher affinity. It is expressed exclusively in activated T- and natural killer (NK) lymphocytes.