RAGE, the multiligand receptor of the immunoglobulin superfamily of cell surface molecules,
is implicated in innate and adaptive immunity. Complement component C1q serves roles in
complement activation and antibody-independent opsonization. Using soluble forms of
RAGE (sRAGE) and RAGE-expressing cells, we determined that RAGE is a native C1q
globular domain receptor. Direct C1q–sRAGE interaction was demonstrated with surface
plasmon resonance (SPR), with minimum Kd 5.6 μM, and stronger binding affinity seen in …