CMB2004/L11 Immunisation

Question 1

What kind of immunity is immunisation?

Answer 1

Active artificial

Question 2

Describe passive immunity.

Answer 2

Short-lived (T1/2 3 weeks)
Hypogammaglobulinaemia in infants as maternal IgG declines
IVIgG every 2-4 weeks for immunodeficiency to maintain protective level

Question 3

Describe secondary response in comparison to primary. (3)

Answer 3

Faster to develop
Greater in magnitude
May be qualitatively better (high affinity)

Question 4

What can immunity protect? (2)

Answer 4

The individual
The population

Question 5

Give 2 complications of measles.

Answer 5

Ear infection - hearing loss
Pneumonia
Sub-acute sclerosing panencephalitis (SSPS) - CNS complication

Question 6

Describe how herd immunity helped overcome measles.

Answer 6

1st vaccine introduced 1963
MMR introduced 1988
83-94% vaccinated to prevent outbreaks

Question 7

Give 3 requirements of an effective vaccine.

Answer 7

Safe
High level of protection
Long-lasting protection
Right type of response
Low cost
Easy to administer
Minimal side effects

Question 8

What does an inactivated vaccine contain?

Answer 8

Dead organisms

Question 9

What does a subunit vaccine contain?

Answer 9

Protein fragments
E.g., Hepatitis B

Question 10

What does a toxoid vaccine contain?

Answer 10

Bacterial toxin
E.g., tetanus

Question 11

What does a conjugate vaccine contain?

Answer 11

Something with low antigenic property covalently bound to something with high
E.g., S. pneumoniae diptheria

Question 12

Give 2 features and an example of inactivated vaccines.

Answer 12

Important antigens must survive killing
May have side effects
Being replaced by new vaccines
E.g., Salk polio vaccine

Question 13

Give an example of an attenuated vaccine.

Answer 13

Vaccinia (smallpox)
Sabin (polio, drop on tongue with sugar)
MMR
BCG (tuberculosis)

Question 14

Give 2 pros to live vaccines.

Answer 14

Single dose effective
May be given by natural route
May induce local and systemic immunity
May induce right type of response

Question 15

Give 2 cons to live vaccines.

Answer 15

Reversion to virulence
Possibility of contamination
Susceptible to inactivation
Causes disease in immunocompromised host

Question 16

How is polio spread?

Answer 16

Faeco-oral route

Question 18

Describe polio.

Answer 18

Member of picornviridae
+ve sense RNA translated into large polypeptide which is cleaved post-translation
Most infectious subclinical

Question 19

Give an example of a subunit vaccine.

Answer 19

Hepatitis B - surface antigen
Pneumococcal polysaccharide - Pneumovax

Question 20

Give an example of a toxoid vaccine.

Answer 20

Tetanus toxoid - inactivated protein endotoxin from bacteria

Question 21

Give an example of a conjugate vaccine.

Answer 21

Hib (Haemophilus influenzae type B)
MenC
Pneumococcal conjugate vaccines (Prevnar 13)

Question 22

Describe conjugate vaccines.

Answer 22

Capsular polysaccharide conjugated to protein
Converts Thymus-independent (TI) TI-2 polysaccharide antigen to a thymus dependent form

Question 23

Describe how conjugate vaccines work. (4)

Answer 23

B cell binds bacterial polysaccharide epitope linked to tetanus toxoid protein
Antigen internalised and processed
Peptides from protein component presented to T cell
Activated B cell produces antibody against polysaccharide antigen on surface of bacterium

Question 24

Give an example of a vaccine which induced the wrong kind of immune response.

Answer 24

1960s vaccine for respiratory syncitial virus
Vaccinated children suffered more serious infections with RSV

Question 25

What is reverse vaccinology?

Answer 25

Whole genome screening to identify proteins that could be used as vaccines
Approach used to develop vaccine against Neisseria meningitidis group B

Question 26

What are adjuvants?

Answer 26

A substance administered with an antigen to promote immune response

Question 27

How do adjuvants help vaccines?

Answer 27

Pure antigens often elicit weak immune responses
Provide a depot
By immunostimulatory properties

Question 28

Via which mechanisms can adjuvants work? (3)

Answer 28

Activate dendritic cells via TLRs or NLRs
Cause release of endogenous danger signals
Promote antigen uptake by dendritic cells
Stimulate release of chemokines/cytokines
Promote ‘cross-presentation’ of exogenous antigens by class I

Question 29

Give 2 adjuvants used in animals.

Answer 29

Freunds adjuvant: oil in water emulsion
Freunds complete adjuvant: also contains mycobacteria

Question 30

Give an adjuvant used in humans.

Answer 30

Alum most common
Aluminium hydroxide/phosphate
Better for Ab responses than cell-mediated immunity

Question 31

Give a newer adjuvant used clinically.

Answer 31

MF59 (Novartis) Squalene based oil in water emulsion
AS03 (GSK) includes squalene and vitamin E
AS04 (GSK) alum plus monophosphoryl lipid A (LPS derivative)

Question 32

Give 2 recent additions to routine immunisations in the UK.

Answer 32

MenB
Men ACWY
Influenza
Shingles
RSV

Question 33

Give 2 at-risk groups who are offered additional vaccines.

Answer 33

Travellers
‘At risk’ groups
Healthcare workers

Question 34

What is the viral vector in the Oxford/AZ SARS-CoV2 vaccine?

Answer 34

ChAdOx1 with CMV vector

Question 35

Which 2 SARS-CoV2 vaccines were mRNA vaccines?

Answer 35

Moderna
Pfizer/BioNTech

Question 36

What does an attenuated vaccine contain?

Answer 36

Live but virulence disabled organisms
E.g., BCG vaccine