Intro to Host Defense

Question 1

3 external immune mechanisms

Answer 1

1. Special anatomical structures
2. Behavioral adaptations
3. Reproductive bursts

Question 2

3 internal immune mechanisms

Answer 2

1. Dealing with invading pathogens
2. Removing worn-out cells
3. Identify and remove abnormal or mutant cells

Question 3

Primary cellular elements of adaptive immunity

Answer 3

T & B lymphocytes

Question 4

3 functions of acquired immunity

Answer 4

1. Specific recognition of foreign antigens
2. Immunological memory of infection
3. Pathogen-specific adaptor proteins

Question 5

3 bad things that come from acquired immunity

Answer 5

1. Allergies
2. Autoimmunity
3. Tissue graft rejection

Question 6

Innate immune system distinguishes between?

Answer 6

“Infectious non-self” and “non-infectious self”

Question 7

3 cells which trigger innate immunity (via inflammatory responses mainly)

Via what receptors?

Answer 7

1. Neutrophils
2. Macrophages
3. Mast cells

Via host defense surveillance receptors

Question 8

Adaptive immune response is generally mediated by the same cells used for innate immunity, but in what different way?

Answer 8

Molecularly-specific receptor systems

Question 9

Innate immune mechanisms are abundant in what tissue?

Answer 9

Barrier tissues:

1. Skin
2. Epithelial tissues of gut and respiratory

Question 10

Innate immune mechanisms delay need for acquired immune response how and for how long?

Answer 10

3-5 days for clonal expansion and differentation of effector lymphocytes

Question 11

General mechanisms of innate immunity

Answer 11

1. Barrier tissue and glands
2. Inflammation
3. Complement system
4. Interferons (antiviral effector proteins)
5. NK cells
6. Symbiotic bacteria (“natural flora”)

Question 12

How does epidermis contribute to innate immunity?

Answer 12

1. Keratinized epithelial cells form physical barrier and chemically detoxifies potential carcinogens
2. Melanocytes absorb UV light
3. Keratinocytes are immune-sensing

Question 13

How does dermis contribute to innate immunity?

Answer 13

1. Sweat and sebaceous glands secrete antimicrobial peptides

2. Abundant blood vessels participate in inflammation

Question 14

How does genitourinary system contribute to innate immunity?

Answer 14

1. Mucus
2. High salt
3. Low pH
4. Normal flora
5. Antimicrobial peptides

Question 15

How does respiratory tract contribute to innate immunity?

Answer 15

1. Filtering mechanisms in nasal passages
2. Mucus
3. Cilia (mucus escalator)
4. Alveolar macrophages
5. Antimicrobial peptides (in upper and lower respiratory tract)

Question 16

How does GI tract contribute to innate immunity?

Answer 16

1. Paneth cells (epithelial cells in upper GI which produce antimicrobial peptides)
2. Lysozyme in saliva
3. Gastric acid
4. Commensal flora in upper GI, rumen and/or large intestine

Question 17

Paneth cells

Answer 17

Epithelial cells in upper GI which produce antimicrobial peptides

Question 18

Classic signs of inflammation

Answer 18

1. Tumor (swelling)
2. Rubor (redness)
3. Calor (heat)
4. Dolor (pain)
5. Loss of function

Question 19

Rubor

Answer 19

Redness

Question 20

Calor

Answer 20

Heat

Question 21

Dolar

Answer 21

Pain

Question 22

Goals of inflammatory response

Answer 22

1. Isolate, destroy and/or inactive invaders
2. Remove debris
3. Prepare tissue for healing and repair

Question 23

Histamine functions

Answer 23

1. Increase local blood flow → increases delivery of inflammatory cells and mediators
2. Increase capillary permeability to deliver inflammatory mediators to extracellular space

Question 24

Mast cells are resident in tissue and do what functions:

Answer 24

1. Release histamine

2. Release cytokines

Question 25

Cytokines

Answer 25

Attrach other inflammatory cells (macrophages and neutrophils)

Question 26

Localized edema arises from?

Answer 26

1. Increased colloid osmotic pressure in extracellular space 2. Increased capillary blood flow 3. Increased capillary permeability

Question 27

How does localized edema contribute to pain?

Answer 27

Distends tissue

Question 28

What is inflammation (in a very micro sense)

Answer 28

Leaked plasma in interstitial space clots

Question 29

Locations of pattern recognition receptors

Answer 29

1. Cell surfaces 2. Intracellular compartments 3. Secreted into bloodstream and tissue fluids

Question 30

Principal specific functions of pattern recognition receptors

Answer 30

1. Opsonization 2. Activation of complement and coagulation pathways 3. Phagocytosis 4. Activation of proinflammatory signaling pathways 3. Apoptosis induction

Question 31

Acute-phase proteins are produced by?

Answer 31

Liver during early stages of infection and inflammation

Question 32

Acute-phase secreted pattern recognition proteins

Answer 32

1. Mannan-binding lectin (MBL) 2. Serum amyloid protein (SAP) 3. C-reactive protein (CRP)

Question 33

2 proteins that can function as opsonins

Answer 33

1. CRP | 2. SAP

Question 34

How do CRP and SAP function as opsonins?

Answer 34

Binding to phosphatidylcholine on bacterial cell surfaces

Question 35

In addition to acting as opsonins, CRP and SAP can also do what?

Answer 35

Initiate classical complement pathway

Question 36

What does MBL do?

Answer 36

1. Bind to terminal mannose residues on microbial surfaces | 2. Associates with complement-initiating serine protease

Question 37

Why is there a need for intracellular pattern recognition proeins?

Answer 37

Viruses and some bacterial pathogens can gain access to intracellular compartments like cytosol

Question 38

Protein kinase R (PKR) function

Answer 38

Binds to and is activated by dsRNA (produced during viral infection) → inactivates eIF2 via phosphorylation

Question 39

Muramyl dipeptide (MDP)

Answer 39

Bacterial cell wall component → binds to and activates NOD2 (nucleotide-binding oligomerization domain)

Question 40

TLR4 (toll-like receptor 4) KNOW ME

Answer 40

Recognies LPS

Question 41

LPS

Answer 41

Lipopolysaccharide → component of bacterial cell walls (mainly gram-neg) which induces powerful inflammatory responses, shock and death

Question 42

TLR2 recognizes:

Answer 42

1. Bacterial cell-wall peptidoglycan 2. Bacterial lipoproteins 3. Some LPSs 4. Glycophosphotidylinositol from T. cruzi 5. Yeast cell wall zymosan

Question 43

TLR5 (KNOW THIS)

Answer 43

Recognizes flagelin

Question 44

Flagellin

Answer 44

Protein found in bacterial flagellae (on cell surface)

Question 45

TLR9

Answer 45

Recognizes unmethylated CpG motifs present in bacterial or viral DNA

Question 46

How do TLRs signal?

Answer 46

Via pathogen-associated molecular patterns (PAMPs)

Question 47

MyD88

Answer 47

PAMP receptor → causes inflammation, costimulation and antimicrobial genes