M26. Immune response and Vaccinations

Question 1

What are memory cells?

Answer 1

cells that circulate in the blood after an immune response that speed up the response to a subsequent attack by the same pathogen.

Question 2

What are lymphocytes?

Answer 2

white blood cells that circulate round the body in the blood and lymph. B cells mature in the bone marrow, while T cells originate in the bone marrow but mature in the thymus gland.

Question 3

How does an immune response provide long term protection from the disease?

Answer 3

As it produces immunological memory through the release of memory cells which circulate in the blood for a number of years.

Question 4

Which cells detect invading antigens?

Answer 4

T and B lymphocytes

Question 5

Why does it sometimes take some time for the antigens to be detected by T and B lymphocytes?

Answer 5

As there may only be one or two of the particular lymphocytes.

Question 6

What increases the chances of the correct B and T lymphocytes finding the antigen?

Answer 6

As cells that are attacked by the antigen display the antigens on their surface (and macrophages become antigen presenting cells)

Question 7

What is the selection of the correct B and T lymphocytes known as ?

Answer 7

clonal selection as they must increase in numbers before they can become effective at attacking the pathogen (clonal expansion)

Question 8

What is clonal expansion? (how does it occur?)

Answer 8

B and T lymphocytes increasing in numbers before they can become effective at attacking the pathogen (by mitosis)

Question 9

Do B and T lymphocytes manufacture antibodies directly?

Answer 9

no

Question 10

What 3 type of cells do T lymphocytes differentiate into?

Answer 10

T helper
T killer
T memory

Question 11

What 2 type of cells do B lymphocytes differentiate into?

Answer 11

plasma cells/ effector

B memory cells

Question 12

What do T helper cells do?

Answer 12

release cytokines (chemical messangers) that stimulate the B cells to develop and stimulate phagocytosis in phagocytes

Question 13

What do T killer cells do?

Answer 13

they attack and kill the CELLS that have been invaded by pathogens

Question 14

What do plasma cells/ effectors do

Answer 14

flow round in the blood, manufacturing and releasing the antibodies.

Question 15

What do B memory cells do?

Answer 15

they remain in the body for a number of years and act as an immunological memory

Question 16

Why does the immune response takes a few days ? (from lymphocyte selection to plasma cells manufacturing antibodies)

Answer 16

As there are so many steps:

• correct lymphocyte must be selected
• cells must divide to increase in number
• differentiate into plasma cells
• plasma cells manufacture antibodies

Question 17

What is vaccination?

Answer 17

a deliberate exposure to antigenic material, which activates the immune system to make an immune response and provide immunity

Question 18

What is a person described to have when they have been vaccinated? and what is it?

Answer 18

artificial active immunity, which is created by being deliberately exposed to antigenic material that has been rendered harmless, but the immune system treats it as a real disease so produces antibodies and memory cells, which provides long-term immunity.

Question 19

Name the 5 different forms antigenic material can be used in a vaccine

Answer 19

1. whole, live, microorganisms- usually ones not as harmful as those that causes the real disease.
2. a harmless or attenuated version of the pathogenic orgnanism (eg TB or measles vaccines)
3. A dead pathogen (eg typhoid or cholera vaccines)
4. a preparation of the antigens from a pathogen (eg. hepititis B vaccine)
5. some harmless toxin called a toxoid (eg tetanus vaccine)

Question 20

How can vaccines be achieved?

Answer 20

either by injection or orally.

Question 21

What can be vaccination be used for on a large scale

Answer 21

to control disease by providing immunity to all those who are at risk.

Question 22

What are the two main ways for large scale vaccination?

Answer 22

Herd vaccination or ring vaccination

Question 23

What is Herd Vaccination

Answer 23

using a vaccine to provide immunity to all or almost all the population at risk, as once enough of the population is vaccinated, the disease stops spreading.

Question 24

What percentage of the population had to be vaccinated to eradicate smallpox?

Answer 24

80-85%

Question 25

What percentage of people is it thought would have to be vaccinated against measles to eradicate it?

Answer 25

95%

Question 26

Name some examples of vaccination programmes there have been to immunise children against?

Answer 26

TB 
diphtheria
tetanus 
whooping cough 
polio 
meningitis 
measles
mumps
rubella.

Question 27

What is ring vaccination?

Answer 27

vaccinating people in the immediate vicinity of the new cases , which may mean vaccinating people in surrounding houses or even a whole village/town.

Question 28

When is ring vaccination used?

Answer 28

when a new case of a disease is reported.

Question 29

Why are pathogenic organisms constantly a future threat, even if they are already being dealt?

Answer 29

as new strains of the organism can form by mutations, this is most common with viruses

Question 30

What is influenza?

Answer 30

a killer disease caused by a virus that affects the respiratory system

Question 31

After the pandemic of influenze is 1918 that killed 40 million people, what has been done to avoid this reoccuring?

Answer 31

anyone at risk is immunised,, eg those over 65 and 42% of younger people in ‘at risk’ groups.

Question 32

What is passive immunity?

Answer 32

When antibodies are provided by stimulating the immune response, they may have been passed on by the placenta or via breast milk .

Question 33

What is natural immunity?

Answer 33

immunity that is gained in the normal course of living processes, it may be gained as a result of infection that stimulates an immune response

Question 34

What is artificial immunity?

Answer 34

immunity gained by deliberate exposure to antibodies or antigens

Question 35

Give an example of passive natural resistance

Answer 35

antibodies provided via the placenta or via breast milk that makes the baby immune to diseases that the mother is immune to.

Question 36

Why is passive natural resistance so useful in babies?

Answer 36

As it protects them during the first year of a babies life when their immune system is developing.

Question 37

Give an example of active natural immunity

Answer 37

Immunity provided by antibodies made in the immune system as a result of infection.

Question 38

Give an example of passive artificial immunity

Answer 38

immunity provided by injection of antibodies made by another individual eg tetanus injection

Question 39

Give an example of an active artificial immunity

Answer 39

Immunity provided by antibodies made in the immune system as a result of vaccination.
A person is injected with a weakened, dead or similar pathogen, or with antigens, and this activates his or her immune system (ie. immunity to TB and influenza)