Anti-LIR5 antibodies are protein reagents that detect specific antigens. The LIR5 antigen is another term for the human protein leukocyte immunoglobulin like receptor B4, encoded by the LILRB4 gene. The protein is known to be an inhibitory receptor involved in the down-regulation of the immune response and the development of immune tolerance. Canonically, it has an amino acid length of 448 residues and a mass of 49.4 kilodaltons. Its subcellular localization is in the cell membrane. Other alias names for LIR5 include B4, CD85K, and ILT-3.