Innate immunity

Question 1

What is the primary set of cells that differentiates the innate immune system from the adaptive immune system?

Answer 1

Phagocytes

Question 2

Two types of phagocytes

Answer 2

Macrophages and neutrophils

Question 3

Describe four key features macrophages

Answer 3

• Reside in normal cells
• Often the first cells to encounter a pathogen
• Long-lived
• Increase in number during infection

Question 4

Four key features of neutrophils

Answer 4

• Short-lived
• Most abundant type of white blood cell in circulation
• Rarely found in normal tissues
• Can be quickly recruited to the site of an infection

Question 5

Where are tissue-bound phagocytes found?

Answer 5

Located everywhere, but are concentrated in the lung, skin, liver, and spleen

Question 6

Opsonization

Answer 6

Coating of some particles by molecules that enhance recognition by phagocytes

Question 7

What are the mechanisms of opsonization by the innate immune system vs adaptive immune system?

Answer 7

The adaptive immune system coats the particles with proteins from the complement system, and adaptive immune system uses antibodies

Question 8

Mediator production

Answer 8

When activated, immune system cells (mostly macrophages) release cytokines and chemokines, as well as enzymes and peptides that kill foreign cells

Question 9

PAMP recognition

Answer 9

Pathogen associated molecular pattern: have receptors that recognize conserved sequences in many pathogens, such as flagellin, DNA/RNA sequences, etc.

Question 10

Names of PPRs

Answer 10

Toll-like receptors, NOD-like receptors, RIG-I helicase-like receptors, and C-type lectin receptors

Question 11

Definition of inflammation

Answer 11

General term for accumulation of fluid, plasma proteins, and white blood cells in tissues subject to injury

Question 12

What is the intention of inflammation?

Answer 12

To wall off the offending agent

Question 13

To what is inflammation linked?

Answer 13

Tissue repair

Question 14

First step in inflammation process

Answer 14

Vasodilation for the movement of additional mediators and white blood cells to the area of injury

Question 15

Second step in inflammation process

Answer 15

Increased vascular permeability

Question 16

Third step in the inflammation process

Answer 16

Movement of leukocytes into sites of infection

Question 17

What are the main cell types in the site of inflammation through time?

Answer 17

Neutrophil is first, then macrophages, and T cells come later

Question 18

How long does it take for the innate system to be activated?

Answer 18

Can be activated in minutes

Question 19

Which PRRs are transmembrane and which are soluble?

Answer 19

TCRs and CCRs are transmembrane; NCRs and RCRs are soluble

Question 20

On what types of cells are PRRs most likely found?

Answer 20

Macrophages, dendritic cells, and monocytes

Question 21

How do PRRs differentiate DNA between self and non-self?

Answer 21

By the location of the DNA; for example, DNA would be in the nucleus. If there isn’t one, like in bacteria, then it would know it was a non-self cell

Question 22

How does the PRR know what to recruit?

Answer 22

By whatever PAMP is activated; for example, if viral DNA is recognized, the subsequent cytokine release will be for that of cells specialized in killing/sequestering viruses

Question 23

Final common path of pro-inflammatory response

Answer 23

Release of NF-kappa-B

Question 24

One of the most important factors in the inflammatory response

Answer 24

IL-1 beta

Question 25

Activation of IL-1 beta requires activation of what?

Answer 25

The “inflamemasome”

Question 26

What does the inflamemasome do?

Answer 26

Activates a protease called caspase I, which cleaves IL-1 beta to the mature form

Question 27

Most important secreted PRR

Answer 27

Mannose binding lectin (MBL), which activates complement cascade

Question 28

How does the complement system bridge the gap between

Answer 28

• Augmenting antibody response and immunological memory
• Lysing foreign cells
• Clearing apoptotic cells and immune complexes

Question 29

Three pathways to activate the complement system

Answer 29

Classical pathway, lectin pathway, and alternative pathway

Question 30

Classic pathway

Answer 30

Antigen dependent: occurs when C1 interacts with IgM or IgM complexes
Antigen independent: Polyanions (heparin, protamine), gram-negative bacteria, or CRPs react directly with C1

Question 31

Lectin pathway

Answer 31

Mannose binding lectin binds to N-acetylglutamine, fructose, or mannose on bacterial cells, yeast cells, or viruses

Question 32

Alternate pathway

Answer 32

Components of a pathogen’s cell wall cleave C3

Question 33

Final uniting step between the three pathways of complement activation

Answer 33

Cleavage of C3 into C3a and C3b by C3 convertase

Question 34

What does C3b do?

Answer 34

Helps phagosomes bind the pathogen and engulf it

Question 35

Innate-like lymphocytes

Answer 35

They are lymphocytes, but express no or very little diversity in their receptors

Question 36

How many types of ILCs are there?

Answer 36

3

Question 37

Type one ILCs

Answer 37

NK and NKT cells; produce pro-inflammatory cytokines, releases IFN-gamma, and activates DCs

Question 38

Type II ILCs

Answer 38

Release IL-4 and help maturation of DCs

Question 39

Type III ILCs

Answer 39

Releases IL-17, which helps recruit

Question 40

For what do NK cells sample the environment?

Answer 40

Cells that have altered self expression (viral cells, cancer cells)