Vaccines

Question 1

Live vaccines

Answer 1

living but not able to cause disease

Question 2

killed vaccines

Answer 2

killed by heating or chemical exposure

Question 3

Naked DNA vaccines

Answer 3

encodes and makes proteins after injection

Question 4

Sub-unit vaccines

Answer 4

fragments of the micro-organism, e.g. proteins or polysaccharides.
Antibody-mediated immunisation

Question 5

Toxin

Answer 5

Diphtheria toxin (corynebacterium diphtheriae).
Anthrax toxin (Bacillus anthracis).
Tetanus (clostridium tetani).

Question 6

formaldehyde detoxification

Answer 6

cross-link proteins molecules so the toxicity is abolished but the immunogenicity is maintained

Question 7

genetic toxoids

Answer 7

genetically modify toxin but maintain immunogenecity

Question 8

e-toxin

Answer 8

Causes enterotoxaemia in livestock. caused by Clostridium perfingens. Infection in gut, crosses over to cause damage in kidneys and brain.

Question 9

Formaldehyde-treated bacterial culture filtrates

Answer 9

current treatment for enterotoxaemia.

production requires C. perfingens. Low yield. Immunogenicity is low and variable.

Question 10

Indirect assay to test neutralizing antibody

Answer 10

Cature toxin on plate and incubate with monoclonal antibody directed towards toxin. Can sheep serum displace the monoclonal Ab - measure the reduction in signal from monclonal Ab

Question 11

Direct assay to measure neutralizing antibody

Answer 11

Get serum from sheep and incubate with the toxin - mix for 1hr. Use cell culture system to see whether the the toxin is neutralized

Question 12

Y30 -Y196-A168F vaccine

Answer 12

triple mutant genetic toxoid. Y30 and Y196 are in binding domain. A168F are in pore-forming domain

Question 13

advantages of genetic toxoids

Answer 13

not reversible. reproducible. more similar to the molecular structure of the toxin. able to be produced using a less harmful bacterium e.g. E coli. high yield.

Question 14

Diphtheria CRM197 genetic toxoid

Answer 14

Single mutation in the catalytic A-subunit. Glycine to glutaminic acid at residue 52.

Question 15

Plague

Answer 15

Yersinia pestis

Question 16

Subunit vaccine against plague

Answer 16

Multiple subunit. F1 antigen (forms capsule around bacterium). V-antigen (found at the tip of the needle that is in the type III system to inject toxin)

Question 17

F1 and V-antigens

Answer 17

Produced in E.coli by genetic engineering. Need both - seen in mice that they’re not as effective on their own.

Question 18

Antiserum protects mice from plague

Answer 18

Immunise mice with mixture of F1 and V antigens. Allow development of antibodies. Remove serum. Transfer to mice that have not been immunised. Test these mice’s protection. YES.

Question 19

Meningitis B

Answer 19

Neisseria meningitidis B. Traditional vaccinology has failed.

Question 20

Men B reverse technology

Answer 20

Identify 570 ORFs that code for putative secreted/expressed proteins. Purify 350 proteins. Immunise mice and harvest sera. Test for bactericidal activity.

Question 21

Men B vaccine

Answer 21

4CMenB. Bexsero (2013).

Question 22

Polysaccharide subunit vaccimnes

Answer 22

e.g. Streptococcus pneumoniae (pneumonia), haemophilus influenzae (pneumonia), neisseria meningitidis (meningitis) , salmonella typhi (typhoid)

Question 23

23-valent vaccine

Answer 23

pick serotypes that are most likely to cause disease and isolate the polysaccharides from these serotypes

Question 24

polysaccharides are T cell independent antigens

Answer 24

Don’t require CD4 or CD8. polysaccharides directly signal to B cells - clonal proliferation of B cells to produce IgM

Question 25

Problem with polysaccharide subunit vaccines

Answer 25

polysaccharide diversity.

at risk populations have a weak response (elderly and children). no memory

Question 26

Link polysaccharide to protein

Answer 26

Polysaccharide from Streptococcus pneumoniae serotype 9A. + CDM197 (diphtheria genetic toxoid) - protein-polysaccharide conjugate vaccine.

Question 27

glycoconjugates

Answer 27

boost Ab response. Type III polysaccharide of Streptococcus (III). Ovalbumin protein carrier (OVA). conjugate (III-OVA)

Question 28

mechanism of T cell activation by glycoconjugate vaccines

Answer 28

Glycoconjugate is internalised into an endosome of an APC e.g. B cell. Proken down into glycanp-pepties and presented with MHCII. Picked up by alphabeta receptors of CD4+ cells. Activate into Tcarb cells which release cytokines (IL2 and IL4) to mature B cells into memory B cells.

Question 29

CD8-T cell response in vaccines

Answer 29

Live, attenuated microbes (balance between under- and over-attenuation) - use microbes that can invade host cells e.g. tuberculosis (BCG), measles, mumps, yellow fever, polio, influenza).