Immunity and Vaccines

Question 1

What do vaccines contain?

Answer 1

Antigens that cause your body to produce memory cells against a particular pathogen, without the pathogen causing disease - you become immune without getting symptoms

Question 2

What is herd immunity?

Answer 2

Vaccines protect individuals that have them and because they reduce the occurrence of the disease, those not vaccinated are less likely to catch the disease

Question 3

What antigens do vaccines contain?

Answer 3

Antigens that are free or attached to a dead or attenuated pathogen

Question 4

How are vaccines taken?

Answer 4

Injected or taken orally

Question 5

What is the disadvantage of taking vaccines orally?

Answer 5

They can be broken down by enzymes in the gut or the molecules of the vaccines may be too large to be absorbed into the blood

Question 6

What are booster vaccines?

Answer 6

Some booster vaccines are given later on to make sure that memory cells are produced

Question 7

What is antigenic variation?

Answer 7

Pathogens can change their surface antigens. Different antigens are formed due to changes in the genes of a pthogen

Question 8

What does antigenic variation mean for the immune response?

Answer 8

Memory cells from the first infection won’t recognise the different antigens, so the immune system has to carry out a primary response, so you get ill again. It also makes it difficult to develop vaccines

Question 9

How does antigenic variation affect the production of vaccines for influenza?

Answer 9

The flu vaccine changes every year - antigens on the surface of the flu virus change regularly, forming new strains. Memory cells produced from vaccination against one strain will not recognise other strains of the flu - the strains are immunologically distinct. Every year there are different strains of the flu so a different vaccine has to be made

Question 10

What are the two types of immunity?

Answer 10

1. Active
2. Passive

Question 11

What is active immunity?

Answer 11

When your immune system makes its own antibodies after being stimulated by an antigen

Question 12

What are the two types of active immunity?

Answer 12

1. Natural - when you become immune after catching the disease
2. Artificial - when you become immune after being given a vaccine containing the. antigen

Question 13

What is passive immunity?

Answer 13

When you become immune from being given antibodies made by a different organism - your immune system doesn’t produce its own antibodies

Question 14

What are the two types of passive immunity?

Answer 14

1. Natural - when a baby becomes immune due to the antibodies it received from its mother, through the placenta and breast milk
2. Artificial - when you become immune after being injected with antibodies from someone else

Question 15

What are the four differences between active and passive immunity?

Answer 15

1. Active requires exposure to the antigen, passive doesn’t
2. Active takes a while for protection to develop, passive is immediate
3. Active produces memory cells, passive doesn’t
4. Active protection is long-term because the antibody is produced in response to the antigen being present, passive is short-term because antibodies given are broken down