LAG3, also known as CD223, is an immune checkpoint receptor protein primarily expressed in activated T cells NK cells B cells and plasma cell dendritic cells. LAG3 can downregulate T cell activity by binding to MHC II molecules. Meanwhile, LAG3 can also enhance the inhibitory activity of regulatory T cells (Tregs). The use of therapeutic antibodies to inhibit LAG3 can relieve the inhibition of T cells and enhance the body's immune response.
LAG3 is also a new therapeutic target for various malignant tumors.