Immuno + microbio - vaccines + immune BOOSTER drugs

Question 1

R0 = ?

Answer 1

R0 = the average no. of people one sick person will infect

Question 2

To eliminate a disease with a vaccine, what are the requisites of success?

Answer 2

1. vaccine = high immunogenicity
2. Pathogen has no animal reservoir
3. Pathogen must have only 1/small number of strains
4. Must have no latent reservoir

Question 3

Describe herd immunity

Answer 3

If enough people in the population are immunised, this protects unimmunised people from being infected

Question 4

Describe the primary immune response to a pathogen

Answer 4

1. Pathogen is recognised by neutrophils and macrophages by PAMPs and DAMPs
2. Phagocytosis and Ag processing
3. Processed Ag is presented by APCs and recognised by naive T cells –> proliferate + differentiate –> T-helper cells or Cytotoxic T cells
4. T helpers activate B cells which proliferate produce IgM - antigen neutralisation OR Ab-dependent cellular cytotoxicity
5. Cytotoxic t cells kill infected cells

Question 5

Why is T cell memory response so gr8 compared to the primary immune response?

Answer 5

• T memory cells - continue to PROLIFERATE IN ABSENCE OF AG
• T memory cells express cell surface proteins to allow them to migrate to NON-LYMPHOID TISSUES
• T memory cells are EASILY ACTIVATED compared to naiive T cells

Question 6

Why is B cell memory response so gr8 compared to the primary immune response?

Answer 6

• B memory cells = long LIFE SPAN
• B memory cells = more EASILY ACTIVATED
• High levels of PRE-FORMED IgG antibody exist –> therefore quicker response

Question 7

4 features of a perfect vaccine

Answer 7

Easy storage
Good protection
Single injection
No adverse effects

Question 8

With the influenza vaccine, how is protection acquired? Which cell controls the viral load?

Answer 8

Host develops an antibody which binds to viral HA and blocks viral entry into the host cell.

CD8+ T cells control the viral load

Question 9

BCG vaccine - what is actually given and how is response monitored? Which cell mediates the immune response to TB?

Answer 9

Tuberculin injected –> observe skin reaction 48-72 hours later

T-cell mediated response

Question 10

Confirmed adverse reaction to measles vaccine?

Answer 10

Thrombocytopenia

Question 11

Confirmed adverse reaction to rubella vaccine?

Answer 11

Acute arthritis

Question 12

+ves of a live vaccine

Answer 12

• Life long immunity

- Activates all phases of the immune system = good immunogenicity

Question 13

-ves of a live vaccine

Answer 13

• Risk of reversion to virulence
• Cannot give to immunosuppressed/pregnant
• Harder to store

Question 14

E.g.s of live vaccines

Answer 14

MMR, VZV, BCG, yellow fever

Question 15

+ves of inactivated vaccines

Answer 15

• Can give to immunodeficient patients
• Easy storage
• No mutation/reversion
• Can eliminate wild type pathogen from community

Question 16

-ves of inactivated vaccines

Answer 16

Requires boosters + adjuvants

Poor immunogenicity

Question 17

Eg of inactivated vaccines

Answer 17

Pertussis, influenza, rabies

Question 18

Eggs of subunit vaccines

Answer 18

HPV, HepB

Question 19

Eg of inactivated toxoid vaccines - give two

Answer 19

Diphtheria

Tetanus

Question 20

WTF is a DNA vaccine

Answer 20

• Plasmid containing a gene.

- This inserts into a muscle cell, and muscle cell expresses the viral gene –> induces immune response

Question 21

WTF is a conjugate vaccine? how does it work?

Answer 21

Polysaccharide antigen + protein carrier

• PS antigen = produces transient B cell response
• Protein carrier = promotes T cell response, in turn enhancing the B cell response

Question 22

which 2 vaccines must NOT be given to HIV +ve patients

Answer 22

BCG and yellow fever

Question 23

Define an adjuvant

Answer 23

Chance the immune response without altering its specificity

• mimics PAMP activity on TLRs

Question 24

Which adjuvant is most commonly used in vaccination of humans? How does it work?

Answer 24

Aluminium

• Bound to antigen and thus ensures a ‘slow steady stream’ of antigen.
• This helps to prime naive B cells

Question 25

CpG - what is it?

Answer 25

It is an adjuvant - cytosine is phosphate bound to guanine

Activates TLRs on APCs

Question 26

What kind of antigen is associated with better immunogenicity

Answer 26

Protein Ag!

polysaccharide ag have poor immunogenicity

Question 27

How does vaccine schedule affect the host’s protection?

Answer 27

A minimum of 4 MONTHS must be had between the 1st vaccine and a booster

• this allows maturation of B cells + higher secondary response

Question 28

Contraindications to live vaccines

Answer 28

• Immunocompromised patients
• Pregnancy
• Allergy to egg products
• Previous confirmed anaphylaxis

Question 29

2 types of immunoglobulin based therapies used to boost the immune system?

Answer 29

Human normal IgG

Specific Ig

Question 30

How is human normal immunoglobulin given? what kinda Ig is it? Indications?

Answer 30

IV/subcut
IgG from >1000 donors
Indicated in: post BMT, 1ary immune deficiencies, CLL, MM

Question 31

3 examples of recombinant cytokines used to boost the immune response

Answer 31

IFNalpha
IFNbeta
IFNgamma

Question 32

cytokine therapy used in Hepatitis B/C and Kaposi’s sarcoma patients?

Answer 32

IFN alpha

Question 33

Indication for interferon beta therapy?

Answer 33

Relapsing MS

Question 34

Indication for interferon gamma therapy? why is it useful for this?

Answer 34

Chronic granulomatous disease

Boosts killing ability of phagocytes

Question 35

Which cells can be used to boost immune system in post-transplant patients?

Answer 35

T-cell replacement!

Question 36

2 drugs used to block immune checkpoints –> boosts the immune system? Indication?

Answer 36

Ipilimumab
Pembrolizumab

indicated in advanced melanoma

Question 37

MOA of ipilimumab

Answer 37

Blocks CTLA4 (this usually down regulates the immune response)

Question 38

MOA of pembrolizumab

Answer 38

Blocks PD1 (usually down regulates the immune response + promotes tolerance)