Soluble immune complex triggering of a respiratory burst in macrophages: the role of complex aggregation at the...

The capacity of small, soluble immune complexes (SIC) to rearrange into larger aggregates, through additional antibody-antigen bridge formation, on a receptor-bearing cell surface has previously been shown to play an important role in enhancing the uptake and ingestion of SIC by macrophages and has been implicated in the efficient clearance of SIC in vivo. In this report, we extend the study to investigate the role of SIC aggregation in triggering a respiratory burst in macrophages. SIC were found to be more efficient trigger signals than nonaggregating, antigen-free IgG oligomers of similar average size in that they induced a more rapid respiratory burst response that was between 2- and 6-fold greater in magnitude. The implications of these findings are discussed.