Anti-CD5 molecule like antibodies are used in the immunodetection of the protein encoded by the CD5L gene. In humans, the canonical protein has a reported length of 347 amino acid residues and a mass of 38.1 kDa. Its subcellular localization is in the cytoplasm and is also secreted. It is reported to be expressed in spleen, lymph node, thymus, bone marrow, and fetal liver, but not in non-lymphoid tissues. It is reported to be a secreted protein that acts as a key regulator of lipid synthesis: mainly expressed by macrophages in lymphoid and inflamed tissues and regulates mechanisms in inflammatory responses, such as infection or atherosclerosis. Post-translational modifications have been described, including O-glycosylation, N-glycosylation. Other names for this target antigen include API6, CT-2, PRO229, SP-ALPHA, Spalpha, hAIM, CD5 antigen-like, and AIM.