Vaccines

Question 1

What part of immune response do vaccinations rely upon?

Answer 1

Immunological memory

Question 2

Where do B memory cells develop and when?

Answer 2

Germinal centre of lymph nodes

After innate immune response (TFH activation)

Question 3

Why do B memory cells provide quick, strong, long-lived immunity?

Answer 3

They are already class switch, have high affinity and are quiescent

Question 4

What class of Ig dominates adaptive immune response?

Answer 4

IgG

Question 5

What has longer lived memory, antibodies/cell mediated?

Answer 5

Antibodies

Question 6

How was small pox first treated?

Answer 6

Variolation - taking pus from someone with less severe symptoms and giving it to healthy person

Question 7

Why does the cowpox/small pox vaccine?

Answer 7

They both have similar surface antigens so the cowpox immunity works for small pox

Question 8

What 4 things make an effective vaccine?

Answer 8

Safe
Protects against disease (induce antibodies and T cells)
Long-lived protection
practical considerations

Question 9

Neutralising antibodies purpose?

Answer 9

Prevent pathogens entering cells that can’t be replaced

Question 10

Are intracellular pathogens more effected by

a) cell mediated immune system
b) antibodies

Answer 10

a

Question 11

Name 4 methods vaccines are based on?

Answer 11

Killed organisms
Attenuated
Recombinant
Conjugate

Question 12

What is the basis of vaccines from killed organisms?

Negatives

Answer 12

Chemically treat the pathogen so it is no longer pathogenic (can’t replicate)

Need lots of copies of the virus and if not killed properly can cause pathology

Question 13

What is an attenuated virus?

Answer 13

Virus that has been cultured and infected an animal e.g. monkey, until it acquires a mutation that means it doesn’t thrive in humans

Question 14

Why are attenuated viruses effective as vaccines?

Answer 14

They mimic the natural course of infection without causing pathogenesis

Question 15

Why are attenuated viruses not presented with MHC class I?

Answer 15

Don’t release cytotoxic molecules so they are not virulent

Question 16

How are recombinant vaccines made?

Answer 16

Gene for the antigen is isolated and inserted into yeast and yeast are cultured
Modified yeast are selected fro and produce antigen, purified

Question 17

Why is yeast used?

Answer 17

Replicates quickly and has a large chromosome

Question 18

Why are recombinant vaccines safe?

Answer 18

Just an antigen so doesn’t elicit a response

Question 19

Why can encapsulated bacteria evade the immune response?

Answer 19

Coated in peptidoglycan cells (no antigens on surface) so complement not activated (classical pathway) - no opsonisation so no phagocytosis

Question 20

Why are capsular subunit vaccines not effective on children/elderly?

Answer 20

Made from purified specific polysaccharide antigens so doesn’t elicit a proper immune response - IgM only, no class switching, no somatic hypermutation, no memory, Th cells to activate B cells

Question 21

What vaccine is used for encapsulated bacteria?

Answer 21

Conjuaget vaccines

Question 22

What is the basis of conjugate vaccine?

Answer 22

Specific polysaccharide antigen chemically coupled with a carrier protein which amplifies the immune response by developing an environment in which T cells differentiate)

Question 23

Why is injection a bad route of administration for most pathogens?

Answer 23

They normally enter via mucosal surfaces

Injection = systemic - systemic immune response may be inappropriate

Question 24

Why is vaccine by injection not practical?

Answer 24

Expensive, requires skill and pain

Question 25

Why are adjuvants used in vaccines?

Answer 25

Purified antigens do not elicit a strong immune response

Adjuvants are added to elicit inflammation and mimic natural infection to get a better response