C5L2 (C5a receptor-like 2) is a seven-transmembrane orphan receptor, also known as GPR77, which shares significant homology to C5a receptor (CD88). But it is a decoy receptor without G-protein coupling. C5L2 is co-expressed with C5aR on many kinds of cells, such as neutrophils, immature dendritic cells, mast cells, macrophages, and astrocytes. C5L2 binds C5a with similar high affinity as C5aR and relatively higher affinity for C5a-des-Arg than with C5aR. Clone 1D9-M12 is known to block C5a binding to C5L2, but does not react with C5a receptor.