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Updated: Aug 17, 2026
Assessing Anti-fungal Activity of Isolated Alveolar Macrophages by Confocal Microscopy
Published on: July 9, 2014
[Oxygen radical generation of murine alveolar macrophages]
T Murayama1, K Suzuki, K Yamamoto
1Department of Infection and Inflammation, Kyoto University, Japan.
Abstract:
The respiratory burst of murine alveolar macrophages (AM) was compared with that of peritoneal macrophages (PM). Superoxide anion (O2-) released from resident AM was similar to that of resident PM. That is, resident AM or PM exposed to phorbol myristate acetate (PMA) released only a small amount of O2-, whereas both macrophages released a large amount of O2- when stimulated with zymosan particles. AM as well as PM obtained from mice injected with Mycobacterium bovis BCG 3 weeks previously (abbreviated to BCG-AM and BCG-PM, respectively) showed an enhanced killing activity to Candida parapsilosis. O2- release of BCG-AM stimulated with zymosan was similar to that of BCG-PM. In both BCG-AM and BCG-PM, maximal O2- response was obtained by stimulation with a lower concentration of zymosan than the concentration which required for resident macrophages to release maximal amount of O2-. There was however, a remarkable difference between the ability of BCG-AM and BCG-PM to release O2- when stimulated with PMA. Markedly enhanced O2- release of BCG-PM was observed. In contrast, O2- release of BCG-AM exposed to PMA was almost the same as that of resident AM. Hydrogen peroxide release of BCG-AM, when stimulated with PMA or zymosan, was compatible with O2- release. Isoquinolinylsulfonyl piperadine (H-7), an inhibitor of protein kinase C, inhibited O2- release of PMA-stimulated BCG-AM and BCG-PM in a dose-dependent manner and the extent of inhibition was greater in O2- release of PM than that of AM. Superoxide anion release in response to zymosan was slightly inhibited by H-7.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Murine alveolar macrophages (AM) and peritoneal macrophages (PM) exhibit distinct respiratory burst responses. BCG-infected macrophages show enhanced killing activity, but AM display less potent superoxide anion release upon PMA stimulation compared to PM.
Area of Science:
- Immunology
- Cell Biology
Background:
- Macrophages, including alveolar macrophages (AM) and peritoneal macrophages (PM), play crucial roles in innate immunity.
- The respiratory burst, a key microbicidal mechanism, involves the release of reactive oxygen species like superoxide anion (O2-).
Purpose of the Study:
- To compare the respiratory burst activity of murine alveolar macrophages (AM) and peritoneal macrophages (PM).
- To investigate the impact of Mycobacterium bovis BCG infection on macrophage responses to stimulation.
Main Methods:
- Comparison of superoxide anion (O2-) and hydrogen peroxide release from resident and BCG-infected AM and PM.
- Stimulation with phorbol myristate acetate (PMA) and zymosan particles.
- Assessment of the effect of protein kinase C inhibitor H-7.
Main Results:
- Resident AM and PM showed similar O2- release upon zymosan stimulation, with PM exhibiting lower release upon PMA stimulation.
- BCG-infected AM and PM demonstrated enhanced killing of Candida parapsilosis and similar O2- release upon zymosan stimulation.
- BCG-infected PM showed markedly enhanced O2- release upon PMA stimulation, unlike BCG-AM, whose response remained similar to resident AM.
- Protein kinase C inhibition by H-7 reduced O2- release in a dose-dependent manner, with a greater effect on PM compared to AM.
Conclusions:
- Murine alveolar and peritoneal macrophages exhibit differential regulation of the respiratory burst, particularly after BCG infection.
- Alveolar macrophages display a less robust response to PMA stimulation compared to peritoneal macrophages, even when activated.
- Protein kinase C signaling is involved in the respiratory burst of both macrophage types, but its contribution differs between AM and PM.
