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Flashcards in Innate immunity Deck (40):
1

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

Phagocytes

2

Two types of phagocytes

Macrophages and neutrophils

3

Describe four key features macrophages

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

4

Four key features of neutrophils

-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

5

Where are tissue-bound phagocytes found?

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

6

Opsonization

Coating of some particles by molecules that enhance recognition by phagocytes

7

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

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

8

Mediator production

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

9

PAMP recognition

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

10

Names of PPRs

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

11

Definition of inflammation

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

12

What is the intention of inflammation?

To wall off the offending agent

13

To what is inflammation linked?

Tissue repair

14

First step in inflammation process

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

15

Second step in inflammation process

Increased vascular permeability

16

Third step in the inflammation process

Movement of leukocytes into sites of infection

17

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

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

18

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

Can be activated in minutes

19

Which PRRs are transmembrane and which are soluble?

TCRs and CCRs are transmembrane; NCRs and RCRs are soluble

20

On what types of cells are PRRs most likely found?

Macrophages, dendritic cells, and monocytes

21

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

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

22

How does the PRR know what to recruit?

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

23

Final common path of pro-inflammatory response

Release of NF-kappa-B

24

One of the most important factors in the inflammatory response

IL-1 beta

25

Activation of IL-1 beta requires activation of what?

The "inflamemasome"

26

What does the inflamemasome do?

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

27

Most important secreted PRR

Mannose binding lectin (MBL), which activates complement cascade

28

How does the complement system bridge the gap between

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

29

Three pathways to activate the complement system

Classical pathway, lectin pathway, and alternative pathway

30

Classic pathway

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

31

Lectin pathway

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

32

Alternate pathway

Components of a pathogen's cell wall cleave C3

33

Final uniting step between the three pathways of complement activation

Cleavage of C3 into C3a and C3b by C3 convertase

34

What does C3b do?

Helps phagosomes bind the pathogen and engulf it

35

Innate-like lymphocytes

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

36

How many types of ILCs are there?

3

37

Type one ILCs

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

38

Type II ILCs

Release IL-4 and help maturation of DCs

39

Type III ILCs

Releases IL-17, which helps recruit

40

For what do NK cells sample the environment?

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