Paper 1: Topic 3 Infection & response - Monoclonal antibodies (IV form)

Question 1

Explain what monoclonal antibodies are

Answer 1

Clones of a single type of antibody

i.e. they are all exactly the same shape and have the ability to bind to the same antigen

Question 2

Explain how monoclonal antibodies can be produced

Hint: 8 key steps

Answer 2

1. A mouse is injected with the antigen that causes the production of B-lymphocytes that produce the required antibody
2. Cells from the spleen are removed from the mouse as they will have many B-lymphocytes. These cells are called myeloma cells.
3. At the same time as step 1 and 2 cancer cells from a mouse’s bone marrow are grown in specialised petri dishes
4. The B-lymphocytes from the mouse spleen are fused with the myeloma cells to form a hydridoma cell.
5. The hybridoma cells are cultured in a petri dish and form clones
6. The individual hybridoma cells are separated into wells and tested to check it is producing the required antibody.
7. The hybridoma cells that are producing the required monoclonal antibody are cultured in large scale fermenters.
8. The monoclonal antibodies produced by the cloned hybridoma cells are collected and concentrated for use.

Question 3

State 2 advantages of using myeloma cells in producing monoclonal antibodies?

Answer 3

They are long lived

They are capable of rapid replication

Question 4

State 2 uses of monoclonal antibodies

Answer 4

Pregnancy tests

Tests for specific cancers

Question 5

Describe what a hybridoma cell is

Answer 5

A cell formed from the fusion of a tumour cell and B-lymphocyte

Question 6

Explain why tumour cells are used in the production of monoclonal antibodies

Answer 6

They have the ability to replicate rapidly
To produce genetically identical cells
Which can all produce the same specific antibody

Question 7

Give 2 reasons why monoclonal antibodies are so useful in diagnostic tests

Answer 7

Monoclonal antibodies, like all antibodies, only bind to one SPECIFIC antigen

This means they can be used to test for the presence of a specific chemical e.g. protein, hormone, cell

Question 8

Give 3 uses of monoclonal antibodies in laboratory research

Answer 8

They can bind to specific hormones (or other chemicals) to measure their levels in body fluids

They can be used to test blood samples for the presence of specific pathogens

They can be used to locate specific molecules on certain cells or in certain tissues

Question 9

Describe the 4 steps that allow monoclonal antibodies to be used to locate specific molecules in a cell or in a tissue

Answer 9

Monoclonal antibodies specific to the actual molecule that is to be located are produced

Fluorescent markers are added to the specific monoclonal antibodies

If the molecules are present in the sample the monoclonal antibodies will attach to the cells

The fluorescent marker allows the molecules to be detected

Question 10

State 3 advantages of using monoclonal antibodies in cancer treatment

Answer 10

They can be used in some cancer treatments to target specific cells

Healthy cells are not killed as (unlike chemotherapy and radiotherapy which kill normal healthy cells as well as the cancerous cells)

There are less-side effects for the patient

Question 11

Explain the concerns some people have about using monoclonal antibodies in cancer treatment

Answer 11

Monoclonal antibodies do cause more side-effects than were expected e.g. fever, vomiting, low blood pressure

Question 12

State 3 possible side-effects from monoclonal antibody treatment

Answer 12

Fever
Vomiting
Low blood pressure

Question 13

Name the hormone present in the urine of pregnant women that is detected in a pregnancy test

Answer 13

HCG

Question 14

Describe how monoclonal antibodies are used in a pregnancy test

Hint: 6 key steps

Answer 14

The woman urinates over the end of the pregnancy test stick

Inside the test kit are monoclonal antibodies which are specific to HCG. These antibodies have a blue dye attached to them.

The dyed-monoclonal antibodies travel bind to HCG in the urine and travel up the test stick

When they get to the test window in the test strip the dyed-monoclonal antibodies that are bound to HCG bind to other fixed monoclonal antibodies. This causes a blue line to appear in the test window.

Some of the dyed-monoclonal antibodies travel further up the test stick to the test window

Here the dyed-monoclonal antibodies bind to another different fixed antibody. This causes a blue line to appear in the control window.

Question 15

Describe the results you would see in a pregnancy test if the woman is pregnant and the test has worked properly

Answer 15

A blue line in the test window (confirms she is pregnant)
AND
a blue line in the control window (confirms the test has worked properly)

Question 16

Describe the results you would see in a pregnancy test if the woman is NOT pregnant and the test has worked properly

Answer 16

NO line in the test window (confirms she is not pregnant)
AND
a blue line in the control window (confirms the test has worked properly)

Question 17

Describe the results you would see in a pregnancy test if the test has NOT worked correctly

Answer 17

There would be NO blue line in the control window
BUT
there may or may not be a blue line in the test window

Remember if this is the case the woman MUST carry out another test and MUST ignore the results in the test window

Question 18

Describe how monoclonal antibodies are used in a test for cancer

Hint: 5 key steps

Answer 18

Monoclonal antibodies that are specific to the tumour markers are produced

An anti-cancer drug is attached to the monoclonal antibodies

The monoclonal antibodies are given to the patient by an intravenous drip

The monoclonal antibodies bind to the tumour markers on the cancer cells and deliver the drug to the cancer cells

The drugs then kill the targeted cancer cells but do not kill healthy cells

Question 19

Explain what tumour markers are

Answer 19

These are specific antigens found on the outside of cancer cells which are not found on normal healthy cells

Question 20

Describe 3 type of anti-cancer drugs can be attached to monoclonal antibodies to form cancer treatments

Answer 20

Radioactive chemicals

Toxic drug that stops the cancer cell growing or dividing

Chemical that stops the cancer cell growing or dividing