The polyclonal antibody reacts with rat C5L2. The orphan receptor C5L2 is a seven transmembrane receptor with 40% amino acid sequence identity to the C5a receptor, CD88. Expression has been found on granulocytes and immature dendritic cells. In contrast to CD88, C5L2 is uncoupled from G proteins due to an an amino acid replacement of arginine by leucine in the so called DRY region at the end of the third intracellular transmembrane domain. Following C5a binding, C5L2 seems neither to induce classical signalling nor to cause biological responses. When C5L2 was transfected into several cell types, C5a failed to induce chemotaxis, degranulation, or interacellular calcium mobilization. The high affinfity of C5L2 for C5a and its metabolite, C5adesArg and a low affinity for C3a and C3adesArg suggest that this receptor is a scavenger of complement fragments involved in the defence against the harmful side effects of complement activation. C5L2 expression on human neutrophils is known to be decreased in sepsis; loss of expression may be a prognostic indicator in this condition as survivors of sepsis tend to have higher C5L2 levels.