Primary defence Barriers in Periodontal Pathogenesis (2) INNATE Flashcards
What is the most abundant cell in periodontal disease?
neutrophils
How are neutrophils recruited to a site?
chemotaxis by chemokines
How do neutrophils kill bacteria?
They kill bacteria through intracellular (phagocytosis) or extracellular methods using enzymes, free radicals and neutrophil extracellular traps.
What are the extracellular methods of neutrophils killing bacteria?
using enzymes, free radicals and neutrophil extracellular traps.
Can neutrophils cause exaggerated response?
YES
LEADING TO TISSUE DAMAGE
Describe the steps in neutrophil adhesions and rolling, leading to diapedesis
- attachment to the endothelial wall - neutrophils PSGL-1 to endothelial P/E-selectin (low affinity)
- rolling - neutrophil LFA-1 to to endothelial ICAM-1
- diapedesis and chemotaxis
- phagocytosis and apoptosis
What is chemotaxis?
cells move along a chemical gradient towards the site of infection
Describe intracellular neutrophil killing?
Neutrophils internalise bacteria through phagocytosis.
They release enzymes and oxygen radicals (degranulate) within the cells inside membrane bound phagosomes
If these enzymes and free radical are released, they may damage host tissues.
What protective mechanism do neutrophils have?
As a protective mechanism, neutrophils have enzyme inhibitors and antioxidants
phagocytosis also, to prevent host damage
What happens if the enzymes and free radicals leak into host tissues?
cause host damage
What happens if there is an issue with antioxidants?
tissue damage due to ROS
When does neutrophil extracellular killing occur?
This happens when the bacterial mass is too large for phagocytosis.
Neutrophils degranulate extracellularly and release enzymes and oxygen
What is the main cause of periodontal tissue breakdown?
extracellular neutrophil killing
What are the APC ?
macrophages
dendritic cells
B cells
What are the functions of macrophages?
They scavenge dead cells
They function similar to neutrophils
They link innate and adaptative immunity by functioning as antigen presenting cells thus activating specific immunity