Concepts of vaccination

Question 1

What vaccines are used for non-infectious diseases?

Answer 1

• anti-allergy vaccines
• canine malignant melanoma vaccine
• anti-LHRH or -gonadotrophin vaccine for repro control
• cavvine against steroid androstenedione to increase sheep fertility

Question 2

Why is it sometimes difficult to target a vaccine to a specific species/animal?

Answer 2

• e.g. target for a BVD is cows but what age, stage of production, breed?
• a pathogen may affect various species e.g. salmonella
• the ultimate target might be one species but the vaccine is given to another e.g. badgers and cows

Question 3

What type of immunity do intracellular and extracellular pathogen stages prime?

Answer 3

• intracellular - cell-mediated
• extracellular - antibody mediated

Question 4

What is natural and artificial passive immunisation? What are the adv and disadv?

Answer 4

• natural: maternally derived in colostrum/ via placenta
• artificial: injection of antibodies from resistant to susceptible animal
• Adv:
  
  • immediate protection
• Disadv:
  
  • only a few weeks of protection
  • antibodies wane
  • no cell mediated immunity
  • only target EC pathogens

Question 5

What are the approved products for passive immunity?

Answer 5

• Botulism
• rabies
• tetanus
• venom
• • • immediate but transient effect
    • used for treatment or post-exposure
• but can lead to type I/II hypersensitivites

Question 6

What is active immunisation?

Answer 6

• stimulation of APCs
• both T and B cells stimulated
• helper and effector responses to several epitopes
• crucial memory responses developed

Question 7

What must vaccines activate?

Answer 7

• innate immune system and APCs
• delivery of antigen alone will result in T cell anergy rather than activation

Question 8

What is an adjuvant?

Answer 8

• a pharmacological/ immunological agent that enhances the immune response while keeping the injected foreign material to a minimum
• some (alum and emulsions) generate depots that allow slow release of antigen in orfer to continure the stimulation of the immune system
• also increase recruitment and activation of APCs
• alum- bind antigens to form multi-molecular aggregates which will encourage APC uptake

Question 9

What are the adjuvants used in vet med?

Answer 9

• water/oil emulsions
• organic
• inorganic (alum)
• pathogen recognition receptor ligands (PAMPs)

Question 10

What are the different types of vaccine that can be made?

Answer 10

Question 11

What are the features of Inactivated whole pathogen vaccines?

Answer 11

• safe
• less immunogenic
• have to be administered more often
• outcome antibody focussed
• need adjuvants for effective immunity

Question 12

What are the features of a Live attenuated vaccine?

Answer 12

• modified pathogen (attenuated) by:
  
  • heat
  • chemical
  • culture
  • direct genetic mod
  • adapting to different host
• use close relative of pathogen

Question 13

What is Rinderpest?

Answer 13

• cattle plague
• viral disease
• member of Morbillibirus genus
• present with four Ds

Question 14

What is a Recombinant vector vaccine?

Answer 14

Question 15

What happens with DNA vaccines?

Answer 15

Question 16

WHat is a Protein subunit vaccine?

Answer 16

Question 17

What is DIVA?

Answer 17

• differentiating infected from vaccinated animals
  
  • most vaccines are inactivated or attenuated forms of pathogen- therefore often impossible to differentiate
  • A DIVA/ marker vaccine- allows for the differentiation

Question 18

List some problems with vaccines

Answer 18

• cost
• poor immunirt (parvovirus vaccine)
• immunity doesnt stop infection
• antibodies contribute to disease
• vaccine interferes with serodiagnosis (FMDV - no DIVA)