Immunity and Vaccines

Question 1

What happens to your body without a vaccine?

Answer 1

Whilst B-cells are dividing to produce enough antibodies to deal with the pathogen, you suffer from symptoms of the disease

Question 2

What do vaccines contain?

Answer 2

Vaccines contain antigens that cause your body to produce memory cells against a particular pathogen, without the pathogen causing disease

Question 3

What is herd immunity?

Answer 3

Vaccines protect individuals that have them, because they reduce the occurrence of the disease, without the pathogen causing disease. Those not vaccinated are also less likely to catch the disease because there are fewer people to catch it from

Question 4

What state are the antigens in, in the vaccine?

Answer 4

The antigens may be free or detached to a dead or attenuated pathogen

Question 5

How can vaccines be taken?

Answer 5

Vaccines can be taken orally or injected

Question 6

What is the disadvantage to taking vaccines orally?

Answer 6

The vaccine could be broken down by enzymes in the gut or the molecules of the vaccine may be too large to be absorbed into the blood

Question 7

Why are booster vaccines given?

Answer 7

Booster vaccines are given to make sure that memory cells are produced

Question 8

Antigens on the surface of pathogens activate what?

Answer 8

The primary response. When you’re infected a second time by the same pathogen they activate the secondary response

Question 9

What is antigenic variation?

Answer 9

Some pathogens are able to change their surface antigens - these changes are due to changes in the genes of the pathogen. This antigen variability is called antigenic variation

Question 10

How does antigenic variation affect the secondary response?

Answer 10

Antigenic variation means that when you’re infected a second time, the memory cells produced from the first infection will not recognise the different antigens. So the immune system has to carry out a primary response against the new antigens

Question 11

Antigenic variation makes it difficult to develop what?

Answer 11

Vaccines

Question 12

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

Answer 12

1. The influenza vaccine changes every year because the antigens on the surface of the influenza virus change regularly, forming new strains of the virus
2. Memory cells produced from vaccination with one strain will not recognise other strains with different antigens. The strains are immunologically distant
3. Every year there are different strains of the influenza virus circulating in the population, so a different vaccine has to be made
4. New vaccines are developed and one is chosen every year that is the most effective against the recently circulating influenza viruses
5. Governments and health authorities implement a programme of vaccination using the most suitable vaccine

Question 13

Give the two types of immunity

Answer 13

1. Active immunity

2. Passive immunity

Question 14

What is active immunity?

Answer 14

This is the type of immunity you get when your own immune system makes its own antibodies after being stimulated by an antigen

Question 15

What are the two types of active immunity?

Answer 15

1. Natural - when you become immune after catching the disease
2. Artificial - when you become immune after you’ve been given vaccination containing a harmless dose of the antigen

Question 16

What is passive immunity?

Answer 16

This is the type of immunity you get from being given antibodies made by a different organism - your immune system doesn’t produce antibodies on its own

Question 17

What are the two types of passive immunity?

Answer 17

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

Question 18

What are the four differences between active and passive immunity?

Answer 18

1. Active immunity requires exposure to the antigen where as passive immunity doesn’t
2. It takes a while for protection to develop in active immunity where as it is immediate in passive immunity
3. In active immunity memory cells are produced where as memory cells are not produced in passive immunity
4. In active immunity protection is long term because the antibody is produced in response to a complimentary antigen being in the body. In passive immunity protection is short term because the antibodies given are broken down