Primary defence Barriers in Periodontal Pathogenesis (2) INNATE

Question 1

What is the most abundant cell in periodontal disease?

Answer 1

neutrophils

Question 2

How are neutrophils recruited to a site?

Answer 2

chemotaxis by chemokines

Question 3

How do neutrophils kill bacteria?

Answer 3

They kill bacteria through intracellular (phagocytosis) or extracellular methods using enzymes, free radicals and neutrophil extracellular traps.

Question 4

What are the extracellular methods of neutrophils killing bacteria?

Answer 4

using enzymes, free radicals and neutrophil extracellular traps.

Question 5

Can neutrophils cause exaggerated response?

Answer 5

YES

LEADING TO TISSUE DAMAGE

Question 6

Describe the steps in neutrophil adhesions and rolling, leading to diapedesis

Answer 6

1. attachment to the endothelial wall - neutrophils PSGL-1 to endothelial P/E-selectin (low affinity)
2. rolling - neutrophil LFA-1 to to endothelial ICAM-1
3. diapedesis and chemotaxis
4. phagocytosis and apoptosis

Question 7

What is chemotaxis?

Answer 7

cells move along a chemical gradient towards the site of infection

Question 8

Describe intracellular neutrophil killing?

Answer 8

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.

Question 9

What protective mechanism do neutrophils have?

Answer 9

As a protective mechanism, neutrophils have enzyme inhibitors and antioxidants

phagocytosis also, to prevent host damage

Question 10

What happens if the enzymes and free radicals leak into host tissues?

Answer 10

cause host damage

Question 11

What happens if there is an issue with antioxidants?

Answer 11

tissue damage due to ROS

Question 12

When does neutrophil extracellular killing occur?

Answer 12

This happens when the bacterial mass is too large for phagocytosis.
Neutrophils degranulate extracellularly and release enzymes and oxygen

Question 13

What is the main cause of periodontal tissue breakdown?

Answer 13

extracellular neutrophil killing

Question 14

What are the APC ?

Answer 14

macrophages
dendritic cells
B cells

Question 15

What are the functions of macrophages?

Answer 15

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

Question 16

Where do mast cells reside?

Answer 16

all connective tissues

Question 17

What granule factors does an activated mast cell produce?

Answer 17

Granules include neutrophil chemotactic factors, histamine and heparin