Immunisation

Question 1

types of immunisation

Answer 1

passive

active/vaccination

Question 2

passive immunisation

Answer 2

administration of pre formed immunity from one person/animal to another persoon

Question 3

limitations of passive immunity

Answer 3

only antibody mediated (will not work if cell mediated)

Question 4

ad/dis of passive immunisation

Answer 4

dvantages
- gives immediate protection
- effective in immunocompromised patients
Disadvantages
- short lived
- possible transfer of pathogens
- ‘serum sickness’ on transfer of animal sera

Question 5

how are the antibodies made for passive immunisation

Answer 5

1) Human normal immunoglobulin
- prepared from pools of at least 1000 donors
- serum contains antibodies against diseases

Question 6

types of vaccines for active immunisation

Answer 6

non living vaccinces

live attenuated vaccines

Question 7

non living vaccines

Answer 7

whole killed and toxids
herpes virus
SARS -CoV-2

Question 8

humoral antibody repsocne

Answer 8

1) Antigen presenting cell takes in antigen via phagocytosis
2) presents on the APC surface with MHC II
3) T cell receptor correct shape detects antigen
4) TCR of niave T cell binds to Ag
5) signalling
6) Niave T cell becomes activated and turns into primed Th2 cell

Question 9

T and B cell cooperation and AB production

Answer 9

1) B cells can internalise and present the same antigen with MHC class 2 – primed to the Th2 cells
2) Th2 cells secrete cytokines (which interact with the B cells) Il4/5/10/13
3) These cause B cells to divide, clonal expansion and differentiate into plasma cells and memory B cells
4) Plasma cells secrete antibody that have high specific to the antigen
Antibodes made are specific to the antigen

Question 10

primary vs secondary immune repsocne

Answer 10

Primary immune response

• low antibody production
• memory B cells made

Secondary immune response
- larger and quicker response

Question 11

latent perido

Answer 11

where the cells are making the antibodies and recognising the antibodies

Question 12

how can bacteria or viruses be inactivated

Answer 12

formaldehyde or B-propioactone

- cross links but retains shape

Question 13

problems and limitations of whole kills vaccines

Answer 13

• organisms must be grown to high titre in vitro (viruses and some bacteria difficult/expensive to grow in the lab)
• whole pathogens can cause excessive reactogenicity (i.e. adverse reactions, excessive immunological responses, can cause disease in itself)
• immune responses are not always close to the normal response to infection eg no mucosal immunity - no CD8 Tc response
• usually need at least 2 shots and regular boosters

Question 14

what is attenuation

Answer 14

where an organisms is cultured in such a way it does not cause disease when inoculated into humans

Question 15

advantages of live attenuated vaccines

Answer 15

1) immune response more closely mimics that following real infection because its not mixed no shape change
2) better immune response so lower doses are required so scale of in vitro growth needed is lower
3) route of administration more favourable (oral
4) fewer doses may need to be given for immunisation

Question 16

problems and limitations of of live attenuated vaccines

Answer 16

• often impossible to balance attenuation and immunogenicity (attenuation may mean Ab will not recognise the real thing)
• reversion to virulence (pathogenic form)
• transmissibility
• live vaccines may not be so attenuated in immunocompromised host

Question 17

why is it hard to develop vaccines

Answer 17

• pathogen too difficult to grow in culture
• killed pathogen not protective (shape change)
• impossible to obtain attenuated and suitability immunogenic strain
• too many strains causing disease
• cost

Question 18

novel vaccine approaches

Answer 18

1) recombinant proteins
2) synthetic peptides
3) live attenuated vectors
4) mRNA vaccines
5) polysaccharide- protein conjugates

Question 19

reconbinant protein uses

Answer 19

protein from the bacteria/vruses used

• just need the DNA to make the protein
• difficult to find proton that are protective and genaerate a strong immune response

Question 20

synthetic peptides and problems

Answer 20

peptides synthesised directly using a machine
-	avoids the need for pathogen growth
Problems
-	identifying protective epitopes
-	inducing a strong or broad response

Question 21

live attenuated vectors - viral vectors

+ how does it work

Answer 21

Composed of a safe living attenuated viruses that have inserted genes encoding forgein antigens, which are displayed to the immune system

Attenuated genetically stable vaccine vector able to take additional forgein DNA
- this encodes the desired antigen/protein
When injected the virus is taken up by APC, the viral DNA is released and enters the nuclear
- viral DNA is transcribed into mRNA and translated to a protein
- some of this spike protein is presented with MHC II on the cell surface as a forgein antigen
- this is recognised by T cells and initiates an immune response to the spike protein
- the virus is replication deficient and cannot replicate in human cells replicating its spread

Question 22

T independent antigens

Answer 22

Bacterial capsular polysaccharides cannot be processed and presented on MHC class II
- however low antibody repsonce, usually IgM

no T cells required for the immune repsonce