ABSTRACT
There are a number of important similarities between the receptors for immunoglobulin (Ig) (described as Fcγ receptors or FcγR) and the complement system. Both biological systems constitute key links between humoral and cellular aspects of the immune cascade, and both play an important role in the processes by which opsonized material, both endogenous and of foreign origin, are identified and processed by the immune system. Detailed discussion of both FcγR and complement biology would be beyond the scope of this chapter, so the focus will be on the role of complement and FcγR in the processing of
immune complexes (IC). Complexes, of course, have a potential to interact with either the complement or the FcγR systems; the former as a consequence of activation of the complement system and the resultant opsonization with complement proteins, and the latter as a consequence of direct interaction of the Fc portion of Ig with the cellular receptors themselves.
