Vaccines 10.11.23

Question 1

Define passive immunity

Answer 1

The administration of pre-formed ‘immunity’ from one person or animal to another person

Question 2

What are the two types of active immunisation?

Answer 2

Non-living vaccines

Live attenuated vaccines

Question 3

Define liver attenuated vaccines

Answer 3

The organisms replicate within the host and induce an immune response which is protective against the wild-type organism but does not cause disease.

Question 4

Define attenuation

Answer 4

Where an organism is cultured in such a way that it does not cause disease when inoculated into humans.

Question 5

Advantages of live attenuated vaccines

Answer 5

Immune response more closely mimics that following real infection because its not fixed – no shape change.

Better immune response so lower doses are required, so the scale of in vitro growth needed is lower.

Route of administration may be more favourable (oral).

Fewer doses may be required to provide protection.

Question 6

Limitations of live attenuated vaccines

Answer 6

• Often impossible to balance attenuation and immunogenicity
• Reversion to virulence
• Transmissibility
• Live vaccines may not be so attenuated in immunocompromised hosts

Question 7

2 examples of live attenuated vaccines - bacterial

Answer 7

THERE ARE ONLY 2

Bacilli Calmette-Guerin (BCG)

Salmonella typhi

Question 8

2 examples of live attenuated vaccines - viral

Answer 8

• Poliomyelitis (Sabin) - widely used to bring polio to the brink of eradication

• Vaccinia virus - used in billions of doses to eradicate smallpox due to cross-reactivity between itself and the variola virus

• Measles, Mumps and Rubella - 3 given together as MMR

Question 9

Define recombinant proteins

Answer 9

Genetically Engineered and produced from bacteria, yeast, insect or mammalian cells

Question 10

Define synthetic peptides

Answer 10

Peptides synthesised directly using a machine - avoids the need for pathogen growth

Question 11

Define live attenuated vectors - viral vector

Answer 11

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

Question 12

Define DNA vaccines

Answer 12

A mammalian plasmid containing DNA that encodes for the foreign protein (yellow) of interest is injected directly.