Immunisation Wk11

Question 1

Immunisation: what are the 2 types of immunisation

Answer 1

• Passive immunisation
  
  • Transfer of antibodies, temporary immunity
• Active immunisation:
  
  • Administration of an antigen > development of immune response
  • Immunity is not immediate
  • Immunity is long-lasting and can be re-stimulated
    vaccine

Question 2

Active immunisation: 2 types of vaccines

Answer 2

• Infectious
  
  • Infecting animal without producing disease
  • Single dose is effective
  • Live virulent, recombinant marker
• Non-infectious
  
  • Requires up to 3 doses
    Killed whole, subunit, naked DNA

Question 3

Active immunisation: list some properties of ideal vaccine:

Answer 3

• Inexpensive
• Consistent formulation
• Stable
• Long shelf life
• Induce appropriate immune response
• Induce long lived immune response
  No adverse effects

Question 4

Live virulent vaccines: what is this?

Answer 4

• Injection of live and virulent infectious agent
  Quite uncommon - injecting animal with the virus- risk of spreading to animal, contamination etc.

Question 5

Live attenuated vaccines:

Answer 5

• Most common
  Intact and viable organism but with reduce virulent

Question 6

Means of attenuation of live vaccines:
‘weakened’ form of germ that causes disease. What are 4 ways this can be achieved?

Answer 6

• Multiple passages through cell culture in which they are not adapted
• Heating
• Use of antigenically related organisms (use of CAV-2 to protect against Cav1)
  Deletion of modification of virulence using molecular techniques

Question 7

List few disadvantages of infectious vaccines (live)

Answer 7

• Reversion of virulence
• Wrong route of administration
• Less stable
• Specialised storage conditions
  Contamination with another unrelated organism

Question 8

Recombinant organism vaccines:

Answer 8

• Non virulent virus –> viral gene –> recombinant virus with inserted target virus gene –> carrier virus expressing product of inserted gene

Question 9

Marker vaccines; what do they detect? How do we know if its due to an infection or secondary to vaccination (can we even tell?)?

Answer 9

If detect serum antibodies in an animal, are they due to an actual infection or secondary to vaccination?
- Can test for natural expression of the vaccine strain
Are the antibodies different? NO, BUT, we can use certain antibodies with removed proteins to see whether it is naturally occurring virus (will express the protein) and which is just from vaccination (won’t express the protein).

Question 10

Non infectious vaccines: what are these?what is the process for these (3 steps)

Answer 10

• Killed whole organism vaccines - dead virus but still have antigenic structure to stimulate response.

Process:
* Virus is treated with chemicals (formalin, alcohol)
* Killing (but antigenicity is preserved)
* No replication and no pathology, but still antigenic structure that can stimulate immune response in animal

Problems?
Need multiple doses over time as immune response at T0, won’t have long lasting immunity if not replication

Question 11

What are adjuvants in non infectious vaccines

Answer 11

• Need something to boost the immune response - adjuvants required*
  
  • Added to vaccine to boost response
    Usually cause more side effects.

Question 12

What are the differences between live attenuated vaccine and killed vaccines**
Think about storage, immunity, risks, adjuvants, cost, risk of spreading disease etc.

Answer 12

• Live attenuated vaccine:
  
  • More effected immunity, don’t need multiple doses and can be given by natural route
• Killed vaccine:
  
  • More stability on storage
  • Easy to store
  • Lower cost
    BUT require adjuvants and higher doses as don’t multiply

Question 13

Non infectious vaccines: subunit vaccines

Answer 13

• Not containing the entire organism, but only the immunogenic structural protein

Question 14

Adjuvants: what are these?

Answer 14

• Substances added to the vaccine in order to maximise its effective
• Effects:
  
  • Increased speed or magnitude of immune response
  • Reduction of amount of antigen or # doses
  • Establishment of long-term memory of response
• Side effects:
  May cause tissue irritation/lesion

Question 15

Feline injection site sarcoma: example of adjuvant side effects

Answer 15

• Rare side effect of vaccine injection, occurs most commonly with killed vaccines containing adjuvants
• Increased risk with multiple injections
• Induces chronic inflammation, which may be linked to carcinogenesis of FISS
  Meloxicam, cisplatin, long-acting penicillin etc can also induce sarcomas

Question 16

3 adjuvant types are:

Answer 16

1) Depot adjuvants
1. Aluminium salts (insoluble) mixed with Ag
2. Infection > formation of granuloma > slow leakage of Ag into body > prolonged antigenic stimulation
2) Particulate adjuvants
1. Phagocytose particles incorporating with Ag > more effective delivery
3) Immunostimulatory adjuvants
Enhanced cytokine production and selective stimulation of Th1 or Th2 cells

Question 17

4 adverse consequences of vaccines are:

Answer 17

1) Transient pyrexia and lethargy (few days post vaccination)
2) Type 1 hypersensitivity response (pruritus, oedema)
3) Type II or III hypersensitivity reaction
4) Feline injection site sarcoma: especially with FeLV and rabies vaccines; poor prognosis

Question 18

Dog has just been vaccinated but is now developing this disease/has clinical signs for this disease. Why?

List 3 of each the following:
- Vaccine factors
Host factors

Answer 18

• Viruses may have different strains/mutation of the virus so the immune response will not recognise the new strain
• Animal was already infected - so vaccination would not have worked.
• Puppies: maternal antibodies - need to have correct window where you can vaccinate puppies effectively.
  O didn’t wait long enough for vaccine to be effective to take the dog out etc. (e.g. Kennel cough)
• Vaccine factors: improper storage, administration and expiry date
• host factors: maternal antibody interference, immunsuppressed dog, animal incubating disease at time of vaccination