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(OMS1) SFM Exam 2 > Lecture 9: Innate Immunity > Flashcards

Lecture 9: Innate Immunity Flashcards

1
Q

What is the anatomic barrier?

A

Prevents the entry and colonization of many microbes

  • Skin: Sebum produces low pH to inhibit microbial growth
  • Mucous membrane: trap organisms in mucus and propel them out of body
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2
Q

What is inflammation?

A

Complex reaction as a result from any sort of injury

  • Normal conditions: protective
  • Pathological conditions: inflammation is chronic
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3
Q

What are the signs for inlammation

A

Swelling
Redness
Heat
Pain

Due to mast cells producing prostaglandins, leukotrienes, and histamine

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4
Q

What are the steps for an acute inflammatory response? What cells are involved?

A

Step 1: Injury and microbes enter
Step 2: Microbes activate sentinel cells
-Mast Cells
-Macrophages
-Dendritic Cells
Step 3: Sentinel cells secrete inflammatory mediators
Step 4: Increased vascular permeability allows fluid and proteins enter tissues
Step 5: Complement, Abs, and anti-microbial proteins kill microbes
Step 6: Leukocytes enter tissue and kill microbes

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5
Q

What are side effects to inflammation?

A

Pain: due to inflammatory mediators stimulating nerves

Body Reactions: chill, fever, muscle ache

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6
Q

How does fever occur?

A

Infection triggers production of pyrogenic cytokines:

TNF, IL-1, IL-6 in macrophages

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7
Q

How do innate immune cells recognize non-self cells?

A

Innate cells look for PAMPs

  • unique to pathogens
  • cannot be altered
  • no structural similarity to self Ags
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8
Q

How do Toll-Like receptors work?

A

Step 1: Recognize microbes by forming pairs with microbes
(via PAMPs)

Step 2: Activate transcription factors

  • NFkB: promotes various cytokines and adhesion molecules (MOST IMPORTANT)
  • TRIF and MyD 88: Adaptor proteins
  • IRF (interferon): signalling for virus
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9
Q

What does the pairing of TLR 1/2 or TLR 2/6 recognize?

A

Tuberulosis

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10
Q

What does TLR 3 recognize?

A

Certain viruses

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11
Q

What does TLR 4 recognize?

A

Bacteria in GI tract

e.g. E. coli

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12
Q

What does TLR 5 recognize?

A

Bacteria with flagella

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13
Q

What does TLR 7-9 recognize?

A

Certain viruses

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14
Q

Which TLRs recognize extracellular pathogens?

A

TLR 1, 2, 4, 5, 6

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15
Q

Which TLRs recognize intracellular pathogens?

A

TL 3, 7, 8, 9

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16
Q

Which TLRs recognize bacteria?

A

TLR 1, 2, 4, 5, 9

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17
Q

Which TLRs recognize viruses?

A

TLR 3, 7, 8, 9

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18
Q

Which TLRs recognize fungi?

A

TLR 2, 6

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19
Q

What deficiencies in TLR can cause recurring infections?

A

MyD88 and IRAK-4 deficiency

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20
Q

What do NOD-like receptors do?

A

When activated by PAMPs, inflammasomes containing NLR will trigger activation of NFkB and pro-caspase 1.

Caspase 1 will activated IL-1B and IL-18, potent pro-inflammatory cytokines

21
Q

Anti IL-1B and IL-18 therapy is used for what disease?

A

Gout

22
Q

What are DAMPs?

A

Damage associated molecular patterns from dead or dying self cells

  • example: necrosis
  • recognized by macrophages
23
Q

What are the downstream effects of DAMPs?

A

NFkB is activated

Stimulate production of TNF alpha and IL-1

24
Q

What diseases come from DAMPs?

A

Plays role in autoimmune disorders

-Diabetes I, MS, Lupus, Rheumatoid arthritis

25
Q

What are the steps of a PRR triggered response in phagocytes?

A

Step 1: fMET is a prokaryote constituent recognized by immune system
Step 2: Phagocytes bind to pathogen using fMET
Step 3: Initiate phagocytosis

26
Q

What do macrophages produce in response to PAMPs and DAMPs?

A

1) Cytokines and chemokines
2) ROI
3) NO
4) Prostaglandins
5) Cationic proteins and polypeptides

27
Q

What the functions of macrophages?

A

1) Activated by PAMPs and DAMPs
2) Chemotaxis and Tissue Inflammation
3) Phagocytosis, Scavenger function, Tissue repair
4) Effector function
5) Antigen presentation to T cells
6) Immunomodulation

28
Q

How do mast cells react to PAMPs and DAMPs?

A

Express receptors for PAMPs and DAMPs

-can amplify or suppress response

29
Q

Where do mast cells tend to reside?

A
  • Sites exposed to external environment (skin)

- Close to blood vessels (regulate vascular permeability)

30
Q

How do mast cells modulate behavior of nearby cells?

A

1) Release of inflammatory chemicals
2) Increased permeability of neutrophils and monocytes
3) Diapedesis: blood enters
4) Chemotaxis
5) Phagocytosis

31
Q

What activates mast cells?

A
  1. IgE and Ag
  2. PAMPs
  3. Cytokines and chemokines
  4. C3a and C5a complement
  5. Temp and pressure
  6. cell to cell contact
32
Q

What do effector molecules do mast cells release?

A

Early (Seconds):
Histamine
Proteases
TNF

Later (Minutes) :
Prostaglandins
Leukotrienes

Latest (hours):
Cytokines: IL-4 and TNF

33
Q

What are cytokines?

A

Small proteins that mediate inflammation, immunity, and hematopoiesis

  • can work short range and long range
  • both pro and anti inflammatory
34
Q

What are the two important anti-inflammatory cytokines?

A

IL-10 and TGF-B

35
Q

What are the steps in classical complement pathway

A

Step 1: Create C3 convertase (C4bC2a)
Step 2: Create C5 convertase (C4bC2aC3b)
Step 3: Create MAC complex to lyse cell

36
Q

What inflammatory cytokines are important for the acute phase of inflammation?

A

IL-6
IL-1
TNF alpha

37
Q

What acute phase proteins can you measure for a diagnosis of inflammation?

A

C reactive proteins
Serum amyloid A
Mannose Binding protein
alpha 1 acid glycoprotein

38
Q

Where do neutrophils and monocytes enter infected sites of injury?

A

Enter through post-capillary venules

In lungs, liver, and kidney, they enter via capillaries

39
Q

How do neutrophils enter tissue?

A

Leukocyte Extravasation
Step 1: Inflammatory signals (TNF alpha and IL-1) from mast cells are activated
Step 2: Endothelial cells to activate PAF, P-selectin, and E-selectin on surface
Step 3: Leukocytes rolls on endothelial cells until PAF receptor binds with PAF (low affinity)
Step 4: I-CAM on endothelial cells stop leukocytes from rolling and to firmly adhere (high affinity)
Step 5: Leukocyte migrates between endothelial cells to tissue. Follow IL-8 to inflammatory site

40
Q

What activates M1 macrophages (classical)?

A

Induced By:
IFN-gamma cytokines
Microbial products binding to TLR

Produces:
ROS, NO, IL-1, IL-12, IL-23

Result:
Promote inflammation

41
Q

What activates M2 macrophages (alternative)?

A

Induced by:
IL-4 and IL-13

Produces:
IL-10 and TGF-B

Result:
Anti-inflammatory effects

42
Q

How do PRR (patter recognition receptors) play a role in phagocytosis

A

After microbe binds to PRR, microbe undergoes phagocytosis. Lysosome will fuse with phagosome and kill microbe via ROS and NO.

43
Q

How do lysosomes kill microbes?

A
  1. Oxygen consumption is increased
  2. Superoxide anion is produced
  3. Superoxide quickly converted to Hydrogen Peroxide
  4. H2O2 kills microbes
  5. H2O2 is broken down by catalase
  6. Resulting hydroxyl radicals react with organic molecules
44
Q

Is inflammation efficient against intracellular pathogens?

A

ABSOLUTELY NOT

45
Q

How is the anti-viral innate immune response mediated?

A

Type I Interferons alpha and beta
-block viral replication

Natural Killer Cells

46
Q

How do NK cells work?

A

1) NK cells recognize infected cells and kill them through apoptosis
- Via perforins and granzymes
2) NK cells release IFN-gamma to activate macrophages
3) Macrophages kill phagocytized microbes

47
Q

What are NK activating and inhibiting receptors?

A

Activating:
Killer Cell Immunoglobulin-like receptors
e.g. MICA and MICB
-triggers tyrosine kinases

Inhibitory
Class I MHC and Protein Tyrosine Phosphatases

If the binding between KIR and MHC I is strong, host cell will be spared

48
Q

How do cells of innate immunity regulate and adaptive immune response?

A

Signals needed for lymphocyte activation

1) Recognition of microbial antigen by T cell
2) Signal from APC (dendritic or macrophage)
3) Cytokines

(OMS1) SFM Exam 2 (11 decks)

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