Vaccination

Question 1

What is the difference in the adaptive immune response between bacterial and viral cells?

Answer 1

Bacterial and viral infection have the same B cell response, but in bacterial infection, TH1 and Th17 are produced, whereas viral involves Cytotoxic T cells and TH1 mostly

Question 2

How can pathogens avoid the immune response?

Answer 2

Concealment of antigens, antigenic variation, immunosuppression, resistance to the immune response

Question 3

What ways does concealment of antigens occur?

Answer 3

Intracellularly: pathogens inhibit antigen presentation by MHC class I
Privileged sites: hiding dormant in the CNS
Uptake of host molecules: cloak effect

Question 4

How does antigenic variation occur?

Answer 4

Antigenic shift via mutation or drift via recombination

Question 5

How does infliuenza avoid the immune response?

Answer 5

antigenic variation

Question 6

What kind of antigenic variation produces a worse illness?

Answer 6

Antigenic shift, as there is no crossover protection

Question 7

How does immunosuppression occur?

Answer 7

Shielding or inhibition of opsonisation, inhibition of the inflammatory response, induction of T regulatory cells which inhibit antigen presenting to T cells.

Question 8

How does immunosuppression occur in HIV?

Answer 8

CD4 T cells are blocked

Question 9

Why is there usually 2 doses of vaccine required?

Answer 9

Because the first dose stimulates the primary response mediated by B cells and T cells, to produce memory cells. The second dose stimulates the secondary immune response by memory B and T cells

Question 10

What are the different types of vaccination?

Answer 10

Live attenuated
secreted toxins
conjugated
killed/inactivated
subunit
RNA

Question 11

What is a live attenuated vaccine and give an example?

Answer 11

Mutant form of live virus/bacteria that grows poorly in humans. Gives better protective immunity as the virus can replicate real infection. They are fragile, and should not be given to children with weakened immune systems.
EXAMPLE: MMR vaccine

Question 12

What is a killed/inactivated vaccine and give an example?

Answer 12

Virus particles which are unable to replicate in humans because they have been treated chemically or physically. You will always need multiple doses/booster
EXAMPLE: Polio, Hep B

Question 13

What is a secreted toxin vaccine

Answer 13

Secreted toxin vaccines involve purifying bacterial toxins and treating them with formalin to destroy their toxic activity. Inactivated toxoids have sufficient antigenic activity to provide protection against disease

Question 14

What is a Conjugated vaccine

Answer 14

Conjugating bacterial polysaccharide to tetanus/diphtheria. Use capsule to escape CD4/TFH
Produce highly specific IgG antibodies which leads to complement fixation and killing of bacteria.

Question 15

What is a subunit vaccine

Answer 15

Only one part/subunit of the virus rather than the full virus is injected

Question 16

What is an RNA vaccine and give an example?

Answer 16

mRNA vaccines use mRNA created in a laboratory to teach our cells how to make a protein—or even just a piece of a protein—that triggers an immune response inside our bodies
EXAMPLE: COVID-19 vaccine

Question 17

What is the new vaccine for meningitis B based on? How does it work?

Answer 17

Reverse immunology. FHbp prevents activation of the complement. Antibodies with ant FHbp induced with vaccination block FHbp inhibitory functions and allow activation of the complement cascade

Question 18

What is passive vaccination and when is it indicated?

Answer 18

IM/IV injection of antibodies. Indicated for the prophylaxis of infectious disease, to prevent symptoms, protect during incubation period, treat antibody deficiences

Question 19

What is active vaccination and when is it indicated?

Answer 19

iM/IV/SC, introducing the antigen to stimulate a specific response. Indicated as usual vaccines are.

Question 20

What is the purpose of adjuvants and what must they do?

Answer 20

Additional components of vaccines which increase the immunogenicity. Important in subunit vaccines. Must provide appropriate immune response but not induce a response against themselves, but be stable with long shelf, biodegradable, cheap to produce, and reduce vaccine cost.

Question 21

What is the purpose of excipients?

Answer 21

Additives in vaccines to prevent microbial contamination or to stabilise vaccines. Can potentially cause allergic reactions.

Question 22

What makes a good vaccine?

Answer 22

SAFE: vaccine itself must not cause illness or death
PROTECTIVE: vaccine must protect against illness resulting from exposure to live pathogen
GIVES SUSTAINED PROTECTION: protection against illness must last for years
INDUCES NEUTRALISING ANTIBODY: essential to prevent infection
INDUCES PROTECTIVE T CELLS
PRACTICAL: low cost/dose, stability, easy administration, few side effects

Question 23

What is the purpose of the vaccine delivery system?

Answer 23

Protects vaccine from being degraded, a good delivery system can be used to make a prolonged release formulation.

Question 24

What are the different routes of administration of vaccines?

Answer 24

Injection
Intranasal
oral

Question 25

pros and cons of injection delivery

Answer 25

prevent person to person transmission, produce a sytstemic response but they are painful, expensive and they do not mimic pathogen route of entry

Question 26

pros and cons of mucosal vaccination (intranasal/oral)

Answer 26

Produce antibodies in the usual route of delivery but provide less organ protection