Definition

A recombinant humanized immunoglobulin G1 (IgG1) monoclonal antibody directed against the human T-cell-expressed receptor cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4;CTLA4), with potential immune checkpoint inhibitory and antineoplastic activities. Upon administration, anti-CTLA-4 monoclonal antibody IBI310 targets and binds to CTLA-4 expressed on T cells, and inhibits the CTLA-4-mediated downregulation of T-cell activation. This leads to a cytotoxic T-lymphocyte (CTL)-mediated immune response against cancer cells. CTLA-4, an inhibitory receptor and member of the immunoglobulin superfamily (IgSF), plays a key role in the downregulation of the immune system.