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Secretion of lysosomal enzymes induced by immune complexes and complement
Frontiers of Biology
|January 1, 1976
Summary
Immune complexes trigger phagocytosis by neutrophils and macrophages via Fc or C3b receptors, releasing lysosomal contents. This process is a secretory mechanism, not cell lysis, similar to other cell types.
Area of Science:
- Immunology
- Cell Biology
Background:
- Immune complexes activate immune cells like neutrophils and macrophages.
- These cells possess surface receptors (Fc and C3b) for immune complex recognition.
- Phagocytosis is a key cellular response to immune complexes.
Purpose of the Study:
- To elucidate the mechanisms of lysosomal constituent release from phagocytic cells.
- To compare the release process with other cellular secretory pathways.
Main Methods:
- Investigated the interaction of immune complexes with neutrophils and macrophages.
- Observed the role of Fc and C3b receptors in phagocytosis.
- Analyzed the release of lysosomal constituents during phagocytosis and non-phagocytic interactions.
Main Results:
- Phagocytosis of immune complexes by neutrophils and macrophages leads to the release of lysosomal constituents into the extracellular medium.
- In neutrophils, inefficient vacuole closure during phagocytosis results in externalization of granule contents.
- Direct exocytosis of granules occurs when neutrophils encounter large immune complexes or complement components, leading to constituent release.
- The release of lysosomal constituents is a regulated secretory process and does not involve cell lysis.
Conclusions:
- The liberation of lysosomal constituents from neutrophils and macrophages is a secretory process.
- This secretory mechanism is conserved across different cell types.
- Understanding this process is crucial for comprehending inflammatory responses and immune complex-mediated pathologies.
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