Neutrophils - Granules
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Other Cell Types
- Neutrophils - Overview
- Neutrophils - Granules
- Neutrophils - Oxidative Burst
- Basophils
- Eosinophils
- Mast Cells
- Monocytes / Macrophages
- Natural Killer (NK) Cells
- Dendritic Cells
Summary
The granules of neutrophils contain many compounds essential for proper neutrophil function. These molecules include myeloperoxidase or MPO, elastase, lysozyme, NADPH oxidase and lactoferrin. NADPH Oxidase and Myeloperoxidase both play important roles in the oxidative burst of neutrophils, catalyzing the production of reactive oxygen species that are toxic to pathogens. Lysozyme breaks down the walls of bacteria, inducing cell death, while lactoferrin sequesters free iron to slow down bacterial growth. Lastly, elastase works to aid wound healing and tissue remodeling.
Key Points
- Neutrophil Granules
- Degranulation releases contents of these granules
- Primary (azurophilic) granules
- Myeloperoxidase (MPO)
- Produces bleach in Neutrophil Oxidative Burst
- Blue-green pigment responsible for color of pus
- Target of p-ANCA in diseases (e.g. Microscopic Polyangiitis)
- Elastase
- Protease involved in wound healing and tissue remodeling
- Unchecked elastase activity leads to lung damage (emphysema) in alpha-1-antitrypsin deficiency
- Myeloperoxidase (MPO)
- Secondary (specific) granules
- Lysozyme
- Breaks down peptidoglycan cell walls of bacteria
- NADPH oxidase
- Produces superoxide in Neutrophil Oxidative Burst
- Lactoferrin
- Antimicrobial activity by sequestering free iron
- Other hydrolytic enzymes
- Lysozyme