Lecture 7

Question 1

What is a pathogen

Answer 1

Microorganism able to produce disease

Question 2

What is pathogenicity

Answer 2

Ability of a microorganism to cause disease in the host

Question 3

What is virulence

Answer 3

Degree of pathogenicity

Question 4

What are virulence factors

Answer 4

Microbial products that permit the pathogen to cause disease

Question 5

How to promote bacteria colonisation and host disease (6)

Answer 5

1. Contact host cells
2. Adhere to host cells and resist physical movement
3. Invade host cells
4. Compete for resources
5. Resist innate immunity
6. Evade adaptive immunity

Question 6

What prevents specific Abs from binding

Answer 6

Protein A of S.aureus binds Fc to IgG

Question 7

What causes fibrin clot formation

Answer 7

Coagulase of S.aureus

Question 8

What prevent Ab attack

Answer 8

Capsules

Question 9

What clever Abs

Answer 9

Protease

Question 10

How is direct host damaged caused (4)

Answer 10

1. Secrete toxins
2. Endotoxins
3. Direct killing of host cells
4. Physical blockage

Question 11

How is indirect host damaged caused (3)

Answer 11

1. Immune complexes
2. Molecular mimicry
3. Aberrant immune responses

Question 12

How do exotoxins work

Answer 12

Invading bacteria commonly release toxic molecules

Question 13

What effect of toxins does Clostridum tetani cause

Answer 13

Interferes with inhibitory neurons

Question 14

What effect of toxins does Clostridum perfringens cause

Answer 14

Disrupts cell membrane

Question 15

What releases a toxin that acts as a super antigen

Answer 15

S.aureus

Question 16

When does the immediate defence act

Answer 16

0-4 hours

Question 17

When does the early immune response act

Answer 17

4-96 hours

Question 18

How does the later immune response act

Answer 18

Very specific

Question 19

What are the important protective mechanisms of an immune response (4)

Answer 19

1. Complement
2. Pathogen-associated molecular patterns
3. Phagocytes
4. Antibodies and T cells

Question 20

What is a key component of the innate and adaptive immune system

Answer 20

Complement proteins

Question 21

What initiates innate immunity

Answer 21

Interaction between molecules on bacteria and receptor on leukocytes

Question 22

What do leukocytes recognise

Answer 22

PAMPS

Question 23

What signals are PAMPs

Answer 23

Danger signals that trigger innate and adaptive immune responses

Question 24

What are the 4 functions of Ab

Answer 24

1. Neutralisation of bacteria and toxins
2. Opsonisation and phagocytosis
3. Antibody dependent cellular cytotoxicity
4. Ab + complement = classical pathway of complement activation -> lysis of bacteria

Question 25

What are acted onto MHC class II

Answer 25

Exogenous Ag

Question 26

What are loaded onto MHC class I

Answer 26

Endogenous Ag

Question 27

What are recognised by CD8 T cells

Answer 27

Exogenous Ag

Question 28

What are recognised by CD4 T cells

Answer 28

Exogenous Ag

Question 29

Where do CD8 T cells differentiate in

Answer 29

Cytotoxic T cells

Question 30

What to CTLs contain

Answer 30

Cytotoxic granules

Question 31

What are the 3 main types of fungal infection

Answer 31

1. Primary infections, skin and other surfaces 2. Primary infections by dimorphic fungi that causes respiratory infections 3. Secondary infections by opportunistic fungi on immunodeficient animals