Innate Immune System

Question 1

Molecule contained within tears, sweat, and saliva to kill bacteria

Answer 1

Lysopzyme

Question 2

What are liposaccharide and lipoteichoic acid examples of?

Answer 2

PAMP. Pathogen Associated Molecular Patterns

Question 3

Receptors that recognize PAMPs and their locations

Answer 3

Pattern Recognising receptors (PRR):

1. Collectins (blood)
2. Toll like receptors (membrane)
3. Nod like receptors (cytoplasm)

Question 4

What collectins bind to on pathogens

Answer 4

sugar molecules on the surface of the pathogen. Only the ones that have the correct spacing (because there are sugars on host membranes too).

Question 5

What toll receptors bind to

Answer 5

Many components of bacterial microorganisms (flagellin, RNA virus, unmethylated DNA…)

Question 6

What NOD like receptors 1 and 2 bind to.

Answer 6

NOD 1: DAP acid (fatty acid on cell wall of bacteria)

NOD 2: Muramyl dipeptide (constituent of Gram + and - bacteria)

Question 7

What is complement

Answer 7

A series of proteins that circulate in blood, that operate via a cascade of reactions to activate C3 convertase.

Question 8

3 pathways of complement and how they are activated

Answer 8

Classical: antigen antibody complex
MB-lectin: Mannose on pathogen
Alternative: spontaneous activation by pathogen

Question 9

3 roles of C3 converted by C3 convertase

Answer 9

1. Recruitment of phagocytic cells (C3a)
2. Opsonisation, coating of bacteria making it more attractive (C3B)
3. Formation of MAC to lyse the bacteria. (Membrane Attack Complex).

Question 10

Phases of phagocytosis

Answer 10

1. Pathogen is phagocytosed into macrophage
2. fusion of phagosome with lysosome because attracted to conditions inside of it (pH)
3. Digestion of injected microbe
4. Exposure of antigen on surface of cell
5. Discharge of residual body (undigested stuff)

Question 11

Other pathways of killing pathogens in phagocytes

Answer 11

1. O2 radical production to damage DNA and alter bacterial membrane. Causes an oxygen burst
2. NO production also causing damage to bacteria. Catalyzed by L-arginine to L-citrulline

Question 12

Cytokines

Answer 12

Intracellular receptors that bind to specific receptors to activate or deactivate immune response.

Question 13

Chemokines (and example)

Answer 13

Class of cytokines with chemoattractant properties. Attract cells to the site of inflammation. E.g. IL8.

Question 14

Interferons

Answer 14

Class of cytokines produced in response to viral infection. Kill virally infected cells and tumors.

Question 15

2 signals needed to activate Naïve T-cell

Answer 15

1. Antigen presented + MHC

2. Co stimulation, which produced by antigen presenting cell in response to detected PAMPS.

Question 16

Examples of antigen presenting cells.

Answer 16

Macrophages, B Cells and dentritic cells.

Question 17

C4a, C3a, C5a complement what they do

Answer 17

Recruitment phagocytosis

Question 18

C3b complement what it does

Answer 18

lysis

Question 19

C5b, C6, 7, 8 , 9 complement what they do

Answer 19

Membrane attack complex.

Question 20

What cytokines activate inducible nitric oxide synthase and what it does

Answer 20

Interferon gamma and tumor necrosis factor.