2. Innate Immunity

Question 1

Barriers of the innate immunity

Answer 1

• Mechanical: skin
• Chemical: pH of skin 5.5, stomach pH 1.2-3, vagina pH 4.5
• Biological: eg. lactoperoxidase in saliva and colostrums

Question 2

What are soluble antimicrobial molecules?

Answer 2

Amphipathic molecules: positively charged aa’s on one side and negative on the other side -> makes “wormholes” in the membrane
(Defensins)

Question 3

Function of immature dendritic cells

Answer 3

Antigen uptake and processing

Question 4

Function: Mature dendritic cells

Answer 4

Antigen presentation, costimulation, T cell activation

Question 5

Where do we find dendritic cells?

Answer 5

Immature dendritic cells found in peripheral tissues, migrate via afforestation lymphatic to regional lymph nodes -> mature dendritic cells found deep in the cortex

Question 6

Development of macrophages

Answer 6

Myeloid progenitor (bone marrow) -> monocytes (blood) -> tissues: tissue resident macrophages, recruited macrophage (-> classically/alternatively activated)

Question 7

Function: M1 (classically activates)

Answer 7

• Proinflammatory cells
• Promote Th1-Th17 immunity
• Host defense
• Antitumor immunity

Question 8

Function: M2 (alternatively activated)

Answer 8

• Regulates wound healing
• Suppresses T cell responses
• Suppresses host defense and antitumor immunity

Question 9

Apoptosis cells sends … signals

Answer 9

Find me, eat me, tolerate me

Question 10

Three major types of I nnate lymphoid cells

Answer 10

Type I: IFN gamma producers (NK cell)
Type II: IL17 or IL22 producers
Type III: Producers of Th2 cytokines

Question 11

Where can we find innate lymphoid cells?

Answer 11

Mucosa (gut, lungs), skin, adipose and lymphoid tissues

Question 12

What kind of receptor does NK cells have?

Answer 12

Neither B or T receptor. Inhibitory and activating receptors.

Question 13

One inhibitory and one activating NK cell receptor

Answer 13

Activating: NKG2D
Inhibitory: NKG2A

Question 14

Explain frustrated phagocytosis

Answer 14

Eg. a parasite is too large to be taken up in the phagocyte -> phagocyte releases lysosomes to ECS instead

Question 15

Process of endocytosis and phagocytosis

Answer 15

• Endocytosis: receptor binding -> clarhrin coated pit -> endosomes
• Phagocytosis: receptor binding -> actin polymerization -> phagosome
• Golgi sending out lysosomes with hydrologic enzymes
• > endosome, lysosome and phagosome join to form phagolysosome

Question 16

What is opsonization?

Answer 16

Facilitation if phagocytosis by binding of antibody or complement protein to antigen

Question 17

What can we use to cleave the Fc region of the antibody?

Answer 17

Papain

Question 18

Fc gamma receptor

Answer 18

• Bind IgG
• Facilitate phagocytosis
• May suppress the function of B cells

Question 19

Fc epsilon receptor

Answer 19

• Bind IgE

- high affinity form is on mast cells and basophils -> plays a role in allergy

Question 20

PolyIg receptor (Fc receptor)

Answer 20

• Bind polymeric antibodies (IgA)

- Play a role in the transcytosis through the epithelium of the mucous membrane

Question 21

Neutrophil effector functions

Answer 21

Phagocytosis, degranulation, NETs

Question 22

Intravesical killing- oxygen dependent

Answer 22

NADPH oxidase in the mem. of the phagosome -> formation of ROS -> direct killing of microbe inside the phagosome

Question 23

What is pus?

Answer 23

Live and dead neutrophils and tissue debris

Question 24

What disease is caused by phagocyte oxidase deficiency?

Answer 24

Chronic granulomatosus disease (CGD)

Question 25

Three major types of PPRs

Answer 25

Pattern recognition receptors in the membrane, secreted, or intracellular

Question 26

Types of membrane PRRs

Answer 26

Lectin binding receptors, NK cell R, complement Rs, toll like Rs, scavenger Rs

Question 27

Shape, morphology of toll like receptors

Answer 27

Horse shoe shape, leucine rich repeats, well known for PAMP recognition

Question 28

Intracellular PRRs

Answer 28

Nod like receptors (NLR)-> recognition of bacteria, RIG like receptors-> recognition of virus

Question 29

What is an inflammasome and what is it composed of?

Answer 29

Detecting PAMPs and DAMPs. Cytoplasmic multiprotein composed of NOD PRR and proteins like Caspase 1

Question 30

How is the inflammasome activated by DAMPs?

Answer 30

Signal from outside will cause eg. K+ efflux -> activation of NLRP3, ASC and pro-caspase-1 -> release of interleukins (IL- 1beta, IL-18)

Question 31

What are inflammasompathies?

Answer 31

Autoinflammatory diseases with a common feature; release of IL-1beta

Question 32

Where are TLRs located in the gut?

Answer 32

Intracellularly and on the basolateral side of the gut epithelial cells

Question 33

Examples of tissue resident macrophages

Answer 33

Kupffer cells, histiocytes, microglia, osteoclasts

Question 34

Recruited macrophages

Answer 34

Classically activated and alternatively activated

Question 35

Involved in the production of M1

Answer 35

IFNgamma

Question 36

Involved in the production of M2

Answer 36

IL-4, IL-13

Question 37

Innate-like cells

Answer 37

B1 B-cell, marginal zone B cells, iNKT cells, MAIT cells