NCIt definition : A recombinant monoclonal antibody targeting the co-inhibitory receptor lymphocyte-activation
gene 3 protein (LAG-3; LAG3; CD223), with potential immune checkpoint inhibitory and
antineoplastic activities. Upon administration, anti-LAG-3 monoclonal antibody HLX26
targets and binds to LAG-3 expressed by tumor infiltrating lymphocytes (TILs) and
blocks the interaction between LAG-3 and major histocompatibility complex class II
(MHC II) molecules on the surface of antigen-presenting cells (APCs) and tumor cells.
This prevents the negative regulation of T-cell activity that occurs via LAG-3-MHC
II binding and enhances a cytotoxic T-lymphocyte (CTL)-mediated immune response against
tumor cells, leading to a reduction in tumor growth. LAG-3, a member of the immunoglobulin
superfamily (IgSF), negatively regulates both the proliferation and activation of
T-cells. Its expression on TILs is associated with tumor-mediated immune suppression.;