This is the 8th video of chapter 2 of immunology and focuses on Neutrophils and mechanisms of action of Elastase. Granules in Neutrophils, Function of Elastase
The links to the other 7 videos are the following
L2.1: Immunology; Hematopoiesis; Hematopoietic Stem Cell and Common Myeloid-Erythroid Progenitor
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L2.2: Immunology; Hematopoiesis; Hematopoietic Stem Cell (HSC) and Common Lymphoid Progenitor
[ Ссылка ]
L2.3: Immunology; Granulocytes and Agranulocytes; A quick review [ Ссылка ]
L2.4: Immunology; Neutrophils; The first line defender/Granulopoiesis
/Geimsa stain
[ Ссылка ]
L2.5: Immunology; Neutrophils/ Granules/Primary Granules/Azurophilic granules/Myeloperoxidase
[ Ссылка ]
L2.6: Immunology; Neutrophils/ Granules/Primary Granules/Azurophilic granules/Defensins
[ Ссылка ]
L2.7: Immunology; Neutrophils/ Granules/Primary Granules/Azurophilic granules/Lysozymes
[ Ссылка ]
Elastase is an enzyme that belongs to the serine protease family and is involved in the breakdown of elastin, a key component of connective tissues such as skin and blood vessels. Elastase is produced by various cells, including neutrophils, macrophages, and certain bacteria. The enzyme plays a role in tissue remodeling, inflammation, and host defense.
Neutrophils are a type of white blood cell that plays a crucial role in the innate immune system, particularly in responding to bacterial infections. Elastase is one of the proteolytic enzymes released by neutrophils during their immune response. It contributes to the destruction of bacteria through several mechanisms:
Extracellular Killing
Neutrophils release elastase into the extracellular environment, where it can act on bacterial cells. Elastase targets various components of the bacterial cell wall and extracellular matrix.
Degradation of Bacterial Proteins
Elastase cleaves peptide bonds in proteins, including those found in bacterial cell membranes. This enzymatic activity results in the degradation of essential bacterial proteins, leading to loss of structural integrity and functionality.
Disruption of Cell Membrane Integrity
Elastase can target and degrade the lipopolysaccharide (LPS) layer of Gram-negative bacteria or other components of the bacterial cell membrane. This disruption compromises the integrity of the bacterial cell, making it more susceptible to other immune attack mechanisms.
It's important to note that the activities of neutrophil elastase are usually tightly regulated to prevent excessive tissue damage to the host. Dysregulation of these proteolytic enzymes can lead to collateral damage to host tissues, contributing to inflammatory diseases.
In addition to elastase, neutrophils release other antimicrobial substances, such as reactive oxygen species (ROS) and antimicrobial peptides, contributing to the overall bactericidal activity. The coordinated action of these immune components ensures an effective defense against bacterial infections while minimizing damage to host tissues.

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