Local opsonization by secreted macrophage complement components. Role of receptors for complement in uptake of zymosan.

作者：R. Alan B. Ezekowitz, Robert B. Sim, Mark A. Hill, Siamon Gordon · 发表于：The Journal of Experimental Medicine · 年份：1984 · DOI：10.1084/jem.159.1.244 · 被引用次数：207 · 研究领域：Glycosylation and Glycoproteins Research、Complement system in diseases、Monoclonal and Polyclonal Antibodies Research

We have examined the role of macrophage (M phi plasma membrane receptors for the cleaved third complement component (iC3b; CR3) and mannosyl, fucosyl terminated glycoproteins (MFR) in uptake of unopsonized zymosan. Monoclonal antibodies against CR3, M1/70 (Mac-1) and MO1, each inhibited approximately 50% of uptake of 125I-zymosan by murine and human M phi, respectively. Yeast mannan inhibited 0-50% of zymosan uptake in various M phi, in parallel with their expression of MFR. We demonstrated that M phi were the source of C3 in our assay and that the activity of other components of the complement system, namely a C3 convertase, factor I, and a factor I cofactor were also present in serum-free cultures of human monocytes. Macrophage C3 was deposited rapidly, within 10 min, on the zymosan particles and mediated binding, ingestion, and stimulation of superoxide release in BCG-activated and thioglycollate-elicited peritoneal M phi via CR3. Local secretion of complement proteins by M phi themselves can therefore opsonize pathogens and cells able to activate the alternative pathway and effect their destruction.