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Polymorphonuclear neutrophils: an effective antimicrobial force
D W Sawyer1, G R Donowitz, G L Mandell
1Department of Medicine, University of Virginia, Charlottesville 22908.
Abstract:
The production and deployment of polymorphonuclear neutrophils (PMNs) are under close regulation. PMNs interact through cytokines with a number of cell types, including macrophages, lymphocytes, and endothelial cells. PMNs are guided by bacterial products and cytokines to target sites, where microbes are recognized and killed. Killing occurs through oxygen-dependent and oxygen-independent mechanisms. The frequent and severe infections seen in patients with defects (either congenital or acquired) in PMN function demonstrate the importance of PMNs in host defense against infection. PMNs are potent inflammatory cells and can exacerbate disease states such as myocardial ischemia, gram-negative bacterial sepsis, and the adult respiratory distress syndrome.
Insights
Polymorphonuclear neutrophils (PMNs) are crucial for host defense, killing microbes via regulated inflammatory responses. Defects in PMN function lead to severe infections and can worsen inflammatory diseases.
Area of Science:
- Immunology
- Cell Biology
Background:
- Polymorphonuclear neutrophils (PMNs) are key immune cells involved in host defense.
- Their production, deployment, and function are tightly regulated.
- PMNs interact with various cell types like macrophages and endothelial cells via cytokines.
Purpose of the Study:
- To summarize the regulated production and function of PMNs.
- To highlight the role of PMNs in host defense against microbial infections.
- To discuss the involvement of PMNs in exacerbating certain disease states.
Main Methods:
- Review of existing literature on PMN biology and function.
- Analysis of PMN interactions with other cells and signaling molecules.
- Examination of clinical implications of PMN defects and inflammatory roles.
Main Results:
- PMNs are guided to infection sites by bacterial products and cytokines.
- Microbial killing by PMNs involves both oxygen-dependent and independent mechanisms.
- Impaired PMN function is linked to frequent and severe infections.
Conclusions:
- PMNs are essential for effective host defense against pathogens.
- Dysfunctional PMNs contribute to susceptibility to infections.
- PMNs can act as potent inflammatory cells, exacerbating conditions like sepsis and ARDS.