Innate Immunity

Question 1

Describe the response time, specificity and response to repeat infection of the innate immune system

Answer 1

Hours
limited and fixed number of receptors
identical to primary response

Question 2

What do macrophages do?

Answer 2

endocytosis, phagocytosis and clearance

Question 3

What activates the innate immune system?

Answer 3

microorganisms overcome the epithelial barrier and multiply they have pathogen-associated molecular patterns (PAMPs) that are recognized by PAMP receptors on macrophages.
The macrophages then phagocytose the microorganisms and kill them

Question 4

How many PAMP receptors can a macrophage express

Answer 4

it can express multiple PAMP receptors

Question 5

What are the four stages of phagocytosis

Answer 5

1. ) Binding to surface receptors
2. ) engulfment into vacuole/phagosome
3. ) fusion of phagosome with lysosome
4. ) Killing and degradation of bacterium by lysozyme, proteases, acid hydrolases and free radicals

Question 6

What are the cytokines that are released as a result of macrophage activation

Answer 6

IL-1
TNF
IL-6

Question 7

What is the local effect of IL-1

Answer 7

activates vascular endothelium
activates lymphocytes
local tissue destruction
increases access of effector cells

Question 8

What is the systemic effects of IL-1

Answer 8

Fever

production of IL-6

Question 9

What are the local effects of TNF

Answer 9

Activates vascular endothelium
Increases vascular permeability –> increased entry of IgG, complement, and cells to tissue as well as increased fluid drainage to lymph nodes

Question 10

What are the systemic effects of TNF

Answer 10

Fever
Mobilization of metabolites
shock

Question 11

What are the local effects of IL-6

Answer 11

Lymphocyte activation

Increased antibody production

Question 12

What are the systemic effects of IL-6

Answer 12

Fever

Induces acute phase protein production

Question 13

What are some features of Neutrophils

Answer 13

multi lobed nucleus
granulated cytoplasm
stains with acidic and basic dyes
phagocytic 
Main line of defence against invading bacteria

Question 14

What are the two ways Neutrophils and macrophages respond to phagocytic stimuli and describe them

Answer 14

Oxygen dependent: generation of free radicals like superoxide ions and oxygen independent: secretion of hydrolytic enzymes like lysozyme

Question 15

What are the two ways neutrophils find microorganisms with description

Answer 15

1. ) Extravastation - are abundantly in the blood stream and just cross the capillary endothelium to go to site
2. ) Chemotaxis - chemokines are released and bind to cell, the cell then tracks the concentration gradient until it finds the highest concentration of them at the site of infection

Question 16

What are Eosinophils?

Answer 16

polymorphonuclear involved in immunity to parasites and allergic reactions if there is a parasite it will release the vacuoles to the parasite to kill it

Question 17

How is a Mast Cell activated?

Answer 17

The mast cells have FC receptors which bind for the antibody IgE, which can bind the allergen when there is cross linking (two antibodies (IgE) bound to two FC receptors and linked by one allergen) the mast cell degranulates all it’s antibacterial components

Question 18

What do Natural Killer cells target?

Answer 18

virus infected cells
intracellular bacterially-infected cells
tumour cells

Question 19

How do Natural Killer cells attack?

Answer 19

Signals from a cell can be positive or negative and the natural killer cell monitors it if the overall signal from the cell is negative it won’t destroy it if it is positive it will destroy it, it does this by recognizing the receptors on the cell and destroys by releasing granule contents into the other cell through a synapse

Question 20

What is a complement

Answer 20

Set of plasma protein (proteases) that help defend against extracellular pathogens

Question 21

What do complements do when activated?

Answer 21

1. ) attrack phagocytes across local blood vessels
2. ) direct cells to sites of inflammation
3. ) act as opsonins by coating microbes with molecules

Question 22

What is opsonization

Answer 22

the process of being a bridge between bacteria and a macrophage

Question 23

What are the 3 ways complements are activated?

Answer 23

1. ) Classical (Adaptive IS) : Antibody binds to specific antigen on pathogen surface
2. ) Lectin (Innate IS): Mannan-binding protein binds to mannose on pathogen surface
3. ) Alternative (Innate IS): pathogen surface allows complement activation

Question 24

How does a complement cascade destroy a microorganism

Answer 24

complements C5b-9 come and attach to the bacteria and eventually C9 binds puncturing a hole in the bacteria destroying it

Question 25

What are the cells involved in the innate immune response?

Answer 25

``` Macrophages Neutrophils Mast Cells Natural Killer cells Eosinophils Basophils ```

Question 26

What are Defensins

Answer 26

highly positively charged polypeptides that create pores in the membrane of bacteria and kill them mainly found in lower respiratory tract and GIT

Question 27

What are alpha and beta interferons?

Answer 27

Exist viral infected cell and bind to an adjacent cell activated anti-viral state in that cell and it will (with ribonucleases and protein kinase) inhibit viral DNA replication