Immunology

Question 1

Characteristics of innate vs adaptive immunity

Answer 1

Question 2

Phagocytes

Answer 2

Macrophages:
* WBC
* englufs and digests pathogens
* found throughout body
* live several months
* antigen presenting, produce cytokines

Neutrophils: responsible for oral innate immunity
* WBC
* englufs pathogens
* found in bloodstream and tissues
* short lived (few days)
* inflammation is other function

Question 3

Caraicoa-Pazmino 2019

macrophages

Answer 3

• higher macrophages in disease
• macrophage polarization reduced in periodontitis

Question 4

Cell types and key features

Answer 4

Question 5

Toll-like receptors

Answer 5

• innate immune system
• recognized conserved molecular patterns from microbes (PAMPs)
• PAMP+TLR causes activation of macrophages and dendritic cells
• These cells release pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6)

Question 6

TLR and TLR4

Mori 2003

Answer 6

crucial in periodontitis
TLR2 expression elevated in severe perio
TLR2 triggered by p. gingivalis (RANKL stimulation through TLR2 (Kassem et al 2015))
TLR4 associated with A.A.

Question 7

Antimicrobial peptides

Answer 7

• diverse group of naturally occurring peptides that exhibit antimicrobial activity.
• first line of defense

Question 8

Complement proteins

Answer 8

30 plasma proteins
Activated by:
* antibodies
* lectins (bind to carbohydrates of pathogens)
* C-reactive protein: released by liver during inflammation
* bacterial cell surface

Functions:
* opsonization (coats pathogens)
* chemotaxis (attracts phagocytes)
* inflammation (pathogen destruction and tissue repaire)
* Direct killing (MAC)

Question 9

Complement pathways

Merle et al 2015

Answer 9

1. Classical (activated by pathogen-bound antibodies)
2. Lectin (activated by lectins, proteins bound to carbohydrates on surface of pathogen)
3. Alternative (activated by CRP and bacterial surface)

Question 10

Complement pathways

Answer 10

Question 11

Complement and Periodontitis

Answer 11

complement is elevated in perio (Hajishengallis 2015) and reduced after SRP (Hajishengallis 2017)

Question 12

Cytokine functions

Answer 12

1. activate immune cells
2. recruit cells to site of infection
3. promotion of inflammation
4. produce antimicrobial peptides

Question 13

Key cytokines in periodontitis

Answer 13

1. TNF alpha and IL-1: central role in innate IS, active and directs immune cells to sites, inflammation
2. Interferons: inhibit bacterial replication
3. Chemokines: recruit immune cells

Question 14

Cytokine families

Answer 14

Interleukins: cell to cell communication
IL-1, 2, 4, 6, 10

Interferons: antiviral (inhibit replication and spread)
INF alpha, beta, gamma

Tumor necrosis factor: inflammation and cell death
TNF alpha and beta

Chemokines: immune cell migration
IL-8, CCL2,5

Question 15

Types of t-cells

Answer 15

Helper T-cells (CD4+) (B-cell maturation into plasma cells, activat Tc cells)
Cytotoxic T-cells (CD8+) (kill infected cells)
Regulatory T-cells (suppress immune system)
Memory T-cells (remember antigens)

Question 16

Gonzales 2015

Answer 16

Th17 (releases IL17; and IL-22)
IL22 influence osteoclastogensis in chronic perio

Question 17

Factors that reduce perio disease

Alvarez et al 2018

Answer 17

IL-10 and transforming growth factor beta

Question 18

Types of b cells

Answer 18

plasma cells: produce and secrete antibodies
memory cells: store antigens for future needs

Question 19

B cells in perio

Han et al 2006

Answer 19

b-cells activator for receptor of RANKL, lead to osteoclast differentiation

Question 20

Ikebuchi et al 2018

Answer 20

Osteocytic RANKL has important role in osteoclatogenesis during remodelling

vesicular rank, secreted by maturing osteoclasts, binds osteoblastic RANKL and promote bone formation by trigerring reverse signalling through RANKL

Question 21

Antibody classes

Answer 21

1. IgG: most abundant in blood
2. IgM: first responder to pathogen
3. IgA: Found in mucous membranes
4. IgD: antigen receptor on be cells
5. IgE: role in allergies, releases histamine

Question 22

Antibody structure

Answer 22

Y-shaped

four polypeptide chains, two heavy and two light

variable region: located on arms of the Y, recognize and bind to specific pathogen

Constant region: located on the stem of the Y, determine class of antibody

Question 23

Antibody functions

Answer 23

Neutralizations (by binding to key components)

opsonization (aid phagocytes)

agglutination (pathogens clump together)

activate complement

stimulate immune cells

Question 24

Key aspects of adaptive immunity

Answer 24

1. Specificity
2. Memory
3. Diversity
4. Self and non-self discrinimation

Question 25

Cardinal signs of inflammation

Answer 25

1. Redness (rubor) 2. Heat (calor) 3. Swelling (tumor) 4. Pain (dolor) 5. Loss of function (functio laesa)

Question 26

Page and Schroeder 1976

Answer 26

Initial lesion: 2-4 days, leukocyte infiltrates, vasodilation Early lesion (early gingivitis): 4-7 days, neutrophil infiltrate, loss of collagen adjacent JE Established lesion (chronic gingivitis): 2-3 weeks, plasma cells present, loss of collagen fibers Advanced lesion: periodontitis, apical epithelial migration, bone loss

Question 27

RANKL and OPG

Answer 27

RANK (receptor activator of nuclear factor kappa) is a receptor expressed on osteoclasts RANKL is produced by osteoblasts, activated B and T cells, dendritic cells

Question 28

Sui et al 2020

Answer 28

Nanomaterials allow for targetted drug delivery, allowing for low toxiity and ability to promote tissue regeneration

Question 29

Epigenetics of perio

Answer 29

Perio causes lasting changes in myeloid progenitor cells in bone marrow, enhancing immune response.