IgG-coated erythrocytes augment LPS-stimulated TNF-alpha secretion, TNF-alpha mRNA levels, and TNF-alpha mRNA stability in macrophages.
Previous studies have shown that IgG-coated erythrocytes (EIgG) augment the LPS-stimulated increase in serum TNF-alpha levels in animals and the LPS-stimulated secretion of TNF-alpha by isolated macrophages. The present study evaluated the mechanism for the effect of EIgG on LPS-stimulated TNF-alpha secretion in the murine macrophage cell line, RAW 264.7. Incubation of the macrophages with EIgG or IgG-coated glass beads caused a dose-dependent augmentation of LPS-stimulated TNF-alpha secretion. The addition of EIgG increased the rate of LPS-stimulated TNF-alpha protein secretion between 2 and 4 hr after LPS. Accordingly, EIgG increased the levels of TNF-alpha mRNA at 2 and 3 hr after LPS. The increase in the LPS-stimulated TNF-alpha mRNA levels caused by EIgG was associated with an increase in TNF-alpha mRNA stability. Thus, the augmentation of LPS-stimulated TNF-alpha secretion by EIgG was associated with an increase in TNF-alpha mRNA levels which at least partly resulted from an increase in the stability of TNF-alpha mRNA.
Richard
C A
CA
Center for Cardiovascular Sciences, Albany Medical College, Albany, New York 12208, USA.
Wilcox
B D
BD
Loegering
D J
DJ
D000818:Animals; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D004912:Erythrocytes / Q000378:metabolism*; D007074:Immunoglobulin G / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D010587:Phagocytosis; D012333:RNA, Messenger / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D051381:Rats; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D014409:Tumor Necrosis Factor-alpha