Immunology 02 Introduction To Innate Immunity

Front 1

Contrast the receptors of the innate immune system and the adaptive immune system

Back 1

The innate immune system receptors are germ-line encoded, while the adaptive immune system receptors are somatically engineered.

Front 2

Contrast the distribution of the innate and adaptive immune responses

Back 2

The innate distribution is non-clonal, while the adaptive response is clonal

Front 3

Contrast the kinetics of the innate vs adaptive immune responses

Back 3

The innate response is rapid, while the adaptive response is slow due to clonal expansion

Front 4

Contrasts the specificity of the innate immune system vs the adaptive immune system

Back 4

The innate immune system recognizes non-self "pattern recognition". The adaptive system recognizes "altered self". The primary structure is TCR and higher order structures are immunoglobulin and BCR.

Front 5

Contrast the effect cells of the innate immune system and the adaptive immune system

Back 5

All cells are effector cells in the innate system. The effector cells of the adaptive immune system are primarily lymphocytes, dendritic cells, and macrophages.

Front 6

What receptors are important in innate immunity?

Back 6

G-protein coupled receptors (for chemokines and cytokines)
TLRs
Lectins

Front 7

What is the cellular response to G-protein binding in innate immunity?

Back 7

Increased integrin activity, cytoskeletal changes

Front 8

What is the cellular response to TLR binding in innate immunity?

Back 8

Production of cytokines and chemokines

Front 9

What is the cellular response to lectin binding in innate immunity?

Back 9

Production of cytokines and chemokines. Phagocytosis of microbe into the phagosome.

Front 10

What are the most common routes of pathogen entry?

Back 10

Respiratory tract
Digestive tract
Reproductive tract

Front 11

What is the most important cell type in the innate response?

Back 11

Macrophages

Front 12

Describe the half-life and role of macrophages

Back 12

They are long lives and act as sentinal cells

Front 13

Describe the half-life and role of neutrophils

Back 13

They are short lives. They are recruited into tissue to battle infection and in doing so they die. Neutrophils are the biggest component of pus.

Front 14

Describe non-opsonized phagocytosis

Back 14

This is typically mediated by cell surface receptors on leukocytes that recognize repeating carbohydrate subunits on microbes

Front 15

Describe opsonic phagocytosis

Back 15

This is typically mediated by deposition of proteins (e.g. antibodies) on microbes that target them for recognition by specific phagocytic receptors on leukocytes.

Front 16

What are the recognized functions of complement?

Back 16

1. Host defense
2. Clearance of immune complexes
3. Disposal of apoptotic debris
4. Regulation of the immune response

Front 17

Describe the common pathway in complement activation

Back 17

The three pathways all generate C3 convertase. C3 convertase leads to the formation of C3a and C3b.
C3b then forms C5 convertase, making C5a and C5b.

Front 18

What is the first complement pathway activated in an infection? The second? Third?

Back 18

Alternative pathway
Mannose-binding lectin pathway
Classical pathway

Front 19

What does C5a do?

Back 19

C5a increases vascular permeability and is a chemoattractant.

Front 20

What does C5b do?

Back 20

C5b ends up forming a direct pore forming complex that ends up killing the bacteria by forming pores (MAC).

Front 21

What does C3a do?

Back 21

Recruits inflammatory cells

Front 22

What does C3b do?

Back 22

Opsonizes pathogens

Front 23

Which complement proteins form the MAC?

Back 23

C5-9

Front 24

Describe phagocytosis of a pathogen

Back 24

A membrane invagination is created and the pathogen is taken up into a vesicle. This vesicle fuses with a lysosome which has enzymes that can degrade and destroy these bugs. This fusion creates a phagolysosome which is where the bacteria is degraded and removed from the system.

Front 25

What are ROS? What compounds are they?

Back 25

Reactive oxygen species. These are found in the lysosome and can destroy bacteria.
These include: O2-, HOCl, H2O2, O3

Front 26

What is the reactive nitrogen species compound?

Back 26

ONOO-

Front 27

Beyond killing pathogens, what else is macrophage phagocytosis used for?

Back 27

Disposal of dead, apoptotic cells.

Front 28

What is the anti-inflammatory signal when phagocytosing apoptotic cells?

Back 28

TGF-beta

Front 29

Failures in the suppression of inflammation in phagocytosis apoptotic cells can lead to what type of problems?

Back 29

Autoimmune

Front 30

Describe the link between the adaptive and innate immune systems

Back 30

Innate immunity ushers in acquired immune. The innate immune activation of antigen presenting cells results in up-regulation of co-stimulatory molecules and enhances the effectiveness of antigen presentation.

Front 31

What is LPS?

Back 31

Lipopolysaccharide, an important component of gram negative bacteria that is never found in humans.

Front 32

What are PAMPs?

Back 32

Pathogen-associated Molecule patterns

Front 33

What are the important PAMPs for gram positive bacteria?

Back 33

Lipoteichoic acid and certain lipoproteins

Front 34

What family does C1q belong to?

Back 34

The collectin family

Front 35

What is C1q?

Back 35

Subcomponent of complement 1 (C1) which recognizes and binds to the heavy chain of IMMUNOGLOBULIN G or IMMUNOGLOBULIN M initiating the classical complement pathway.

Front 36

Explain the response to a local infection with gram negative bacteria

Back 36

In a local infection activated macrophages secrete TNF-alpha into the tissue. This increases release of plasma proteins into the tissue. Increased phagocyte and lymphocyte migration into the tissue, increased platelet adhesion to blood vessel walls.

Front 37

Explain the response to a systemic infection with gram negative bacteria

Back 37

Activated macrophages in the liver and spleen secrete TNF-alpha into the blood stream. There is then systemic edema causing decreased blood volume, hypoproteinemia and neutropenia, followed by neutrophils. There is decreased blood volume causing collapse of vessels.

Front 38

What is the TLR for LPS?

Back 38

TLR4

Front 39

What is the TLR for lipoprotien

Back 39

TLR1/TLR6

Front 40

Explain how TLRs can respond to a viral infection

Back 40

There are some TLRs inside the cell that can recognize viral components. This can lead to the production of interferons.

Front 41

What is the TLR for dsRNA?

Back 41

TLR3

Front 42

What transcription factor do TLRs trigger?

Back 42

NF-kappaB

Front 43

Describe the two major pathways for TLR signalling?

Back 43

One activated the NF-kappaB leading to production of mostly pro-inflammatory proteins. The other one activates the IRF pathway, leading to production of Type I IFNs.

Front 44

What are NOD proteins?

Back 44

Intracellular peptidoglycan sensors

Front 45

What do NOD-like receptors sense? What do they activate?

Back 45

They sense microbial products and activate the "inflammasome", trigger the maturation of IL-1

Front 46

What are RLRs?

Back 46

RIG-1-like receptors

Front 47

What doe RLRs sense? What do they activate/trigger?

Back 47

RLRs sense viral products, activate the IRF pathway, and trigger production of antiviral proteins

Front 48

What do collectins do?

Back 48

Recognize carbohydrates on pathogen surfaces and perform multiple anti-microbial functions (e.g. opsonization). Collectins are essential for innate immunity, but also help clear apoptotic bodies.