Related Experiment Videos
Formation of the membrane attack complex of complement (MAC) on erythrocytes from monocyte-produced terminal
Scandinavian Journal of Immunology
|June 1, 1987
Summary
Monocytes secrete terminal complement components (C5-C9) that assemble into the membrane attack complex (C5b-9) on antibody-coated target cells. This process leads to cell lysis, demonstrating a novel complement-mediated function of monocytes.
Area of Science:
- Immunology
- Cell Biology
Background:
- The complement system is crucial for innate and adaptive immunity.
- Monocytes are key immune cells involved in host defense.
- The formation of the membrane attack complex (MAC) is a critical step in complement-mediated cell lysis.
Purpose of the Study:
- To investigate whether monocytes can synthesize and secrete terminal complement components.
- To determine if monocytes can assemble the membrane attack complex on target cells.
- To elucidate the role of monocytes in complement activation and cell lysis.
Main Methods:
- Incubation of IgM-coated sheep erythrocytes (EIgM) with serum-free, endotoxin-stimulated monocyte cultures.
- Immunological detection of terminal complement components (C5-C9) and neoantigens using specific antibodies.
- Assessment of cell lysis and the effect of cycloheximide on complement component deposition.
Main Results:
- Terminal complement components (C5-C9) were deposited on EIgM incubated with monocytes.
- C9 neoantigens were detected on EIgM, indicating MAC formation.
- Monocyte-secreted complement components formed the MAC (C5b-9) on EIgM, leading to partial cell lysis.
- Cycloheximide inhibited the deposition of complement components, confirming de novo synthesis.
Conclusions:
- Monocytes actively secrete terminal complement components (C5-C9).
- These secreted components assemble on target cells to form the membrane attack complex (C5b-9).
- Monocytes contribute to complement-mediated cell lysis through the secretion and assembly of the MAC.