Biosynthesis and secretion of complement component (C3) by activated human polymorphonuclear leukocytes.

摘要: We tested the hypothesis that human polymorphonuclear leukocytes (PMN), bearing complement receptors CR1 and CR3, might also synthesize C3, particularly when activated by LPS or cytokines. Northern blot analysis of total RNA, obtained from purified PMN stimulated overnight with cytokines (IFN-gamma, TNF-alpha, IL-1) showed 5.3-kb RNA transcript reported for C3 in hepatocytes monocytes. No transcripts C4 factor B were detected. Time course studies mRNA expression treated TNF-alpha demonstrated a steady increase plateau at 24 h correlated secretion determined ELISA. In contrast, IFN-gamma IL-1 induced transient peak around 8 after stimulation, which was not reflected an increased rate secretion. The content protein culture media, measured ELISA, about 4 ng/ml/10(7) cells stimulation TNF-alpha. A very small amount (about 0.7 cells) detected supernatants unstimulated IFN-gamma- IL-1-induced PMN. Immunoprecipitation polyclonal anti-human followed SDS-PAGE analysis, [35S]methionine labeled PMN, revealed presence three major bands 185, 115 70 kDa, corresponding to pro-C3, alpha beta chains, respectively. Analysis [14C]methylamine incorporation autolytic cleavage produced tissue contained intact thiolester bond. capacity secrete functional response be important mechanism host defense sites inflammation.