QuicKey Pro Human CD5L (CD5 Antigen-like) ELISA Kit (E-OSEL-H0080)

Human CD5 antigen-like protein is a secretory protein that acts as a key regulator of lipid synthesis: it is mainly expressed by macrophages in lymphoid tissues and inflammatory tissues, regulating inflammatory response mechanisms such as infection or atherosclerosis. After entering mature adipocytes via CD36-mediated endocytosis, it binds to FASN in the cytoplasm, inhibiting fatty acid synthase activity, leading to lipolysis, i.e., the degradation of triacylglycerols into glycerol and free fatty acids (FFA). CD5L-mediated intracellular lipid regulation has a direct impact on the transcriptional regulation of the nuclear receptor ROR-γ (RORC). By altering lipid content and limiting the synthesis of RORC cholesterol ligands, it regulates the expression of pro-inflammatory genes in Th17 cells. CD5L is mainly present in non-pathogenic Th17 cells, where it reduces the content of polyunsaturated fatty acid acyls (PUFA), affecting two metabolic proteins MSMO1 and CYP51A1, which synthesize ligands for RORC, thereby limiting RORC activity and the expression of pro-inflammatory genes. By associating with IgM, it interferes with the binding of IgM to Fc alpha/mu receptors, promoting the development of long-lived plasma cells. In addition, it acts as an inhibitor of macrophage apoptosis: in atherosclerotic conditions, it promotes the survival of macrophages from apoptotic effects caused by oxidized lipids. It can also play a role in the early microbial infection response against various pathogens by acting as a pattern recognition receptor and promoting autophagy.