LAG3 Inhibitor
Background
Lymphocyte activation gene 3（LAG-3）is an important immunosuppressive
molecule, mainly expressed on the surface of activated T cells, similar to CD4
molecule structure, and highly binding to major histocompatibility complex (MHC-
Ⅱ). It can negatively regulate the proliferation and function of T lymphocytes and
maintain the stability of its internal environment.
Structure of LAG-3 molecule
LAG-3 is a transmembrane glycoprotein, which belongs to the immunoglobulins
superfamily. It consists of three parts: extracellular region, transmembrane region
and cytoplasmic region. The major histocompatibility complex is a ligand of
LAG-3. The mature LAG-3 molecule consists of 470 amino acids with the relative
molecular weight of 70,000. LAG-3 exists in the form of dimer or oligomer. LAG-3
was also expressed on the surface of NK cells.
Negative regulation of T cells by LAG-3 molecule
LAG-3 molecule can negatively regulate the proliferation and function of activated
T cells and maintain the stability of T cells in the environment. On the surface of
all T lymphocytes, TCR-CD3 complex T lymphocytes recognize antigens by
binding TCR to antigenic epitopes of antigens, and pass activation signal LAG-3
to T cells through CD3 molecules as immunosuppressive molecules. By binding
to TCR-CD3 complex, blocking the signal transduction between CD3/TCR and
TCR-mediated calcium flow, and inhibiting TCR-CD3 complex, the complexes are
involved in antigen recognition and activation signal transmission of T cells.
LAG-3 molecules inhibit immune response by acting on Tregs cells. High
expression of LAG-3 was found on the surface of Treg cells. By enhancing the
inhibitory function of Treg cells and indirectly regulating the proliferation and
function of activated T cells, it was found that LAG-3 expressed on Treg cells
could bind to MHC-Ⅱ molecules on dendritic cells (DC) membrane. It inhibited the
maturation of DC and induced the formation of tolerant DC, which further
inhibited the activation and proliferation of T cells.
