5.5- ANTIBODIES

Question 1

What are antibodies?

Answer 1

proteins with specific binding sites synthesised by B cells

Question 2

What do B cells do when a body is infected by non-self material?

Answer 2

specific antibody

Question 3

What does the specific antibody produced by a B cell do?

Answer 3

reacts with antigen on surface of non-self material by binding to them

Question 4

How many binding sites does an antibody have?

Answer 4

two

Question 5

What are the binding sites of an antibody like?

Answer 5

two identical binding sites

Question 6

What are the antibody binding sites complementary to?

Answer 6

specific antigen

Question 7

How is the massive variety of antibodies possible?

Answer 7

as they’re made of proteins- molecules that occur in almost infinite number of atoms

Question 8

What are antibodies made up of?

Answer 8

four polypeptide chains

Question 9

What is the long chain of one pair of antibodies called?

Answer 9

heavy chains

Question 10

What is the shorter chain of one pair of antibodies called?

Answer 10

light chains

Question 11

What is specific on each antibody?

Answer 11

specific binding site that fits very precisely onto a specific antigen to form antigen-antibody complex

Question 12

Is the binding site the same on different antibodies

Answer 12

no- they’re different

Question 13

As the binding site is different from different antibodies, what are they called?

Answer 13

variable region

Question 14

What does each binding site consist of?

Answer 14

sequence of amino acids that form specific 3D shape that bonds directly to specific antigen

Question 15

What is the rest of the region of the antibody, apart from the variable region known as?

Answer 15

constant region

Question 16

What does the constant region of the antibody bind to?

Answer 16

bind to receptors on cells such as B cells

Question 17

What do antibodies do and not do the antigens?

Answer 17

do not destroy antigens directly but rather prepare antigen for destruction

Question 18

How can antigens assist in the destruction of a bacteria cell? (2)

Answer 18

cause agglutination of cell
clumps of bacterial cells formed, making it easier for phagocytes to locate them as they’re less spread-out within body

then serve as markers that stimulate phagocytes to engulf bacterial cells to which they’re attached

Question 19

Why can monoclonal antibodies be used to target specific substances + specific cells?

Answer 19

as an antibody is very specific to particular antigen (protein)

Question 20

What is one type of cell monoclonal antibodies can target?

Answer 20

cancer cells

Question 21

What is by far the most successful way to treat cancer with monoclonal antibodies?

Answer 21

direct monoclonal antibody therapy

Question 22

What is direct monoclonal antibody therapy? (3)

Answer 22

monoclonal antibodies produced that are specific to antigens on cancer cells

these antibodies given to patient + attach themselves to receptors on their cancer cells

they attach to surface of their cancer cells + block the chemical signals that stimulate their uncontrolled growth

Question 23

Example of a monoclonal antibody used to treat breast cancer?

Answer 23

Herceptin

Question 24

What is the advantage of direct monoclonal antibody therapy?

Answer 24

since antibodies not toxic + are highly specific, they lead to fewer side effects than other forms of therapy

Question 25

What is indirect monoclonal antibody therapy?

Answer 25

involves attaching radioactive or cytotoxic drug to a monoclonal antibody when antibody attaches to cancer cells, it kills them

Question 26

What is a cytotoxic drug?

Answer 26

drug that kills cells

Question 27

What are monoclonal antibodies as those used in indirect monoclonal antibody therapy referred to as?

Answer 27

'magic bullets'

Question 28

Why can monoclonal antibodies used in indirect monoclonal antibody therapy be used in smaller doses?

Answer 28

as they're targeted on specific sites

Question 29

Why is using monoclonal antibodies being used in smaller doses in indirect monoclonal antibody therapy good? (2)

Answer 29

its cheaper + reduces any side effects drug might have

Question 30

Examples of diseases monoclonal antibodies have been used to diagnose? (3)

Answer 30

influenza hepatitis chlamydia infections

Question 31

How quick are monoclonal antibodies in diagnosing diseases in comparison to conventional methods of diagnosis?

Answer 31

much more rapid

Question 32

What are monoclonal antibodies important in diagnosing?

Answer 32

certain cancers

Question 33

What do men with prostate cancer produce more of and what does this lead to?

Answer 33

protein called prostate specific antigen (PSA) leading to unusually high levels of it in blood

Question 34

How can monoclonal antibodies be used to measure the level of PSA in a sample of blood?

Answer 34

using a monoclonal antibody that interacts with this antigen

Question 35

What is a higher than normal level of PSA not diagnostic of, but is "something"?

Answer 35

not itself diagnostic of disease but gives early warning of its possibility + needs for further tests

Question 36

Why is it important for a mother to know as early as possible that she is pregnant?

Answer 36

certain actions she can take to ensure welfare of herself + her unborn baby

Question 37

What can the use of pregnancy testing kits be used for?

Answer 37

early detection of pregnancy

Question 38

What do pregnancy testing kits rely on?

Answer 38

fact that placenta produces hormone called human chorionic gonadotrophin (hCG) + this found in mother's urine

Question 39

What are monoclonal antibodies present on the test strip of a home pregnancy testing kit linked to?

Answer 39

coloured particles

Question 40

What happens if there is hCG present in the urine when using a pregnancy test?

Answer 40

hCG binds to these antibodies

Question 41

What does the hCG-antibody-colour complex do? (pregnancy testing)

Answer 41

moves along strip until it's trapped by different type of antibody creating a coloured line

Question 42

What is used for the production of monoclonal antibodies? (ethical issues)

Answer 42

mice

Question 43

How are mice used in the production of monoclonal antibodies? (ethical issues)

Answer 43

used to produce antibodies + tumour cells

Question 44

What does the production of tumour cells in mice involve? (ethical issues)

Answer 44

deliberately inducing cancer in mice

Question 45

What have monoclonal antibodies be used to successfully treat?

Answer 45

cancer and diabetes

Question 46

Example of deaths associated with use of monoclonal antibodies?

Answer 46

use in treatment of multiple sclerosis

Question 47

As there have been deaths associated with the use of monoclonal antibodies with treatment, what is important regarding patients?

Answer 47

patients have full knowledge of risks + benefits of drugs before giving permission for them to be used (= informed consent)

Question 48

What does testing for safety of new drugs present?

Answer 48

certain dangers

Question 49

What must society use to make decisions about the use of monoclonal antibodies?

Answer 49

ethical issues raised + current scientific knowledge about monoclonal antibodies