Immune System Part III

Question 1

herd immunity:

Answer 1

when the majority of the population is immune to a pathogen, the chances of a susceptible individual contracting an infected individual is low

Question 2

acquired immunity:

Answer 2

immunity you develop during your life

Question 3

active immunity:

Answer 3

immunity you develop after being exposed to an infection or from getting a vaccine

Question 4

passive immunity:

Answer 4

immunity you acquire from someone or something else such as antibodies transmitted from mother to baby through mother’s milk

Question 5

why use passive immunity

Answer 5

• deficiency in antibody synthesis (congenital or acquired)
• insufficient time to wait to mount an active adaptive immune response before complications occur

Question 6

attenuated viruses:

Answer 6

a virus that is still alive but has lost its pathogenicity in humans by being passed through a non-human cell line. when injected as a vaccine provokes an immune response but not the disease.

Question 7

killed viruses:

Answer 7

cannot reproduce. all nucleic acids are inactivated. immune response is often not as potent as attenuated vaccine (boosters often required)

Question 8

what is in a flu shot

Answer 8

primarily inactivated (killed) virus vaccines

Question 9

the flu vaccine has to be:

Answer 9

reformulated every year to reflect the viruses currently circulating in the human populations

Question 10

what does a flu shot do:

Answer 10

generates an antibody response

Question 11

adjuvant:

Answer 11

an ingredient added to the vaccine that activates the innate immune response which is required to generate an adaptive immune response

Question 12

what are the steps of defence in a viral attack:

Answer 12

1. macrophages (should be able to take care of small infections)
2. if that isn’t enough: natural killer cells (activated), and additional phagocytes (neutrophils and more macrophages)
3. signals that this still isn’t enough are: production of interferon and host cells killed by virus infection

Question 13

respiratory viruses:

Answer 13

bind to a ‘normal’ membrane protein and trigger endocytosis. viruses replicate and leave the cell via membrane budding, killing the cell in the process and going on to infect new cells

Question 14

what are rna vaccines

Answer 14

1. the genetic code of a virus is made of RNA. scientists isolate the part of this genetic code that contains instructions for making the virus’s spike protein
2. synthetic RNA which codes for the virus spike protein is packed in lipid nanoparticles. this stops our bodies’ enzymes breaking it down and helps our cells take it in
3. once the synthetic RNA is inside one of our cells, the cell follows the RNA instructions to produce the virus spike protein. its production then triggers an immune response in our bodies

Question 15

what are the benefits and challenges of RNA vaccines

Answer 15

• vaccine production: RNA is easy to make, so RNA vaccines can be developed quicker than other viruses
• safety of the vaccines: RNA can’t cause infection and is broken down by normal processes in our cells.
• storage and transport: some RNA vaccines must be stored at low temperatures to remain stable, which makes storage and transport more challenging