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Hydrogen peroxide-releasing function of chemically elicited and immunologically activated macrophages: differential
Abstract:
Various types of mouse peritoneal macrophages were studied for H(2)O(2) release in the presence of wheat germ lectin or phorbol myristate acetate. Macrophages elicited 3 days before harvest by a single injection of thioglycolate, zymosan A, or a streptococcal preparation (OK-432) were highly responsive to wheat germ lectin, resulting in a marked increase in H(2)O(2) release. However, immunologically activated macrophages induced by double injections of live and heat-killed BCG at 15 and 3 days before harvest or by double injections of zymosan A or OK-432 at 20 and 3 days before harvest did not show any significant response to wheat germ lectin. On the other hand, all macrophages tested responded well to phorbol myristate acetate by augmentation of H(2)O(2) release. Concanavalin A inhibited wheat germ lectin- and phorbol myristate acetate-triggered H(2)O(2) release from all types of macrophages, but inhibition was much more marked in the case of wheat germ lectin-stimulated H(2)O(2) release. Succinylated concanavalin A (divalent concanavalin A) showed only slight suppressive action against macrophage H(2)O(2) release, and prostaglandin E(1) and dibutyryl cyclic adenosine 3', 5'-monophosphate caused depression of H(2)O(2) release from OK-432-induced macrophages.
Insights
Mouse peritoneal macrophages’ hydrogen peroxide (H2O2) release varied based on activation. Thioglycolate-elicited macrophages responded to wheat germ lectin, while BCG-activated macrophages did not, though all responded to phorbol myristate acetate.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Macrophages play a crucial role in the innate immune system.
- Hydrogen peroxide (H2O2) release is a key indicator of macrophage activation.
- Different stimuli can elicit distinct macrophage responses.
Purpose of the Study:
- To investigate the differential H2O2 release from various mouse peritoneal macrophage populations.
- To compare the effects of wheat germ lectin (WGL) and phorbol myristate acetate (PMA) on macrophage H2O2 production.
- To examine the modulatory effects of concanavalin A (ConA) and other agents on macrophage activation.
Main Methods:
- Isolation and elicitation of different mouse peritoneal macrophage populations (thioglycolate, zymosan A, OK-432, BCG).
- Stimulation of macrophages with WGL and PMA to measure H2O2 release.
- Assessment of the inhibitory effects of ConA, succinyl-ConA, prostaglandin E1, and dibutyryl cyclic AMP on H2O2 production.
Main Results:
- Macrophages elicited with thioglycolate, zymosan A, or OK-432 showed high H2O2 release in response to WGL.
- Immunologically activated macrophages (BCG, zymosan A, OK-432) did not respond significantly to WGL.
- All macrophage types exhibited increased H2O2 release upon PMA stimulation.
- ConA significantly inhibited WGL- and PMA-induced H2O2 release, with greater inhibition on WGL response.
- Succinylated ConA had minimal suppressive effects; prostaglandin E1 and dibutyryl cyclic AMP reduced H2O2 release in OK-432-induced macrophages.
Conclusions:
- Macrophage responsiveness to WGL is dependent on the elicitation method.
- PMA is a potent activator of H2O2 release across different macrophage populations.
- ConA acts as a significant inhibitor of WGL- and PMA-mediated H2O2 release.
- Specific signaling pathways modulated by ConA and other agents influence macrophage oxidative burst activity.