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Thromboplastin (factor III) activity in human monocytes induced by immune complexes
European Journal of Clinical Investigation
|June 1, 1982
Summary
Immune complexes stimulate human monocytes to produce apoprotein III, a key part of tissue thromboplastin. This response is strongest at antigen/antibody equivalence, indicating potential signaling beyond the Fc-receptor.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Immune complexes play a critical role in immune responses.
- Tissue thromboplastin (tissue factor) is crucial for coagulation.
- Monocytes are key immune cells involved in inflammation and coagulation.
Purpose of the Study:
- To investigate the effect of immune complexes on apoprotein III synthesis in human monocytes.
- To determine the optimal conditions for immune complex-induced apoprotein III production.
- To explore potential signaling pathways involved in this response.
Main Methods:
- Human monocytes were cultured in vitro.
- Immune complexes were formed using varying antigen/antibody ratios.
- Aprotein III synthesis was measured.
- Experiments using F(ab')2 fragments of immunoglobulins were conducted.
Main Results:
- Immune complexes significantly induced apoprotein III synthesis in human monocytes.
- The maximal induction of apoprotein III (11.1-fold increase) occurred at antigen/antibody equivalence.
- Immune complexes formed with F(ab')2 fragments induced a 4.7-fold increase, suggesting Fc-receptor independent signaling.
Conclusions:
- Immune complexes are potent stimulators of apoprotein III synthesis in human monocytes.
- The Fc-receptor is likely not the sole mediator of this response.
- Further investigation into alternative signaling pathways is warranted.