topic 2 - immunity and vaccines

Question 1

what are vaccines

Question 2

what do vaccines contain, what does this mean

Answer 2

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

Question 3

what is herd immunity

Answer 3

a type of disease immunity that occurs when a large proportion of a population are vaccinated against a disease which prevents the spread of the disease to unvaccinated individuals

Question 4

what are four states of pathogens do vaccines contain

Answer 4

(1) free
(2) attached
(3) dead
(4) attenuated (weakened)

Question 5

what is the disadvantage to taking a vaccine orally

Answer 5

it could 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 may be given later on to make sure that memory cells are produces

Answer 6

booster vaccines

Question 7

what activates primary response

Answer 7

antigens on the surface of pathogens

Question 8

how can the same pathogens evade the immune system after the primary response

Answer 8

by antigenic variation

Question 9

what is antigenic variation

Answer 9

the mechanism by which pathogens alter the proteins or carbohydrates on its surface / different antigens are formed due to the changes in the genes of a pathogen to avoid a host immune response

Question 10

what does antigenic variation result in

Answer 10

the immune system has to start from scratch and carry out a primary response against the new antigens - since the memory cells produced from the first infection will not recognise the different antigens

Question 11

how does antigenic variation affect the production of vaccines (4 points)

Answer 11

(1) memory cells produced from vaccination with one strain of the virus will not recognise other strains with different antigens - the strains are immunologically distinct
(2) every year there’s different strains of the influenza virus circulating in the population so a different vaccine has to be made
(3) new vaccines are developed and chosen every year that is the most effective against the recently circulating virus
(4) governments and health authorities then implement a programme of vaccination using the most suitable vaccine

Question 12

what is active immunity

Answer 12

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

Question 13

what are the two different type of active immunity

Answer 13

natural and artificial

Question 14

what is natural active immunity

Answer 14

when you becomes immune after catching a disease

Question 15

what is artificial active immunity

Answer 15

when you become immune after you’ve been given a vaccination containing a harmless dose of antigen

Question 16

what is passive immunity

Answer 16

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

Question 17

what are the two types of passive immunity

Answer 17

natural and artificial

Question 18

what is natural passive immunity

Answer 18

when a baby becomes immune due to the antibodies it receives from its mother through the placenta and in breast milk

Question 19

what is artificial passive immunity

Answer 19

when you become immune after being injected with antibodies from someone else

Question 20

name four differences between active and passive immunity

Answer 20

(1) active requires exposure to antigen - passive doesn’t
(2) active takes a while for protection to develop - passive protection is immediate
(3) active memory cells are produced - passive they aren’t
(40 active protection is long term as the antibody is produced (after activation in memory cells) in response to complementary antigen being present in the body - passive protection is short term as antibodies given are broken down