Monoclonal antibodies

Question 1

The box jellyfish produces a poison (venom) which enters the blood when a person is stung. A person who has been stung can be treated with an injection of antivenom. This antivenom is produced by injecting small amounts of venom from box jellyfish into sheep, then extracting antibodies from the sheeps’ blood. These antibodies are then injected into the person who has been stung.

(a) If a sheep is injected with the box jellyfish venom on more than one occasion a higher yield of antivenom is obtained. Explain why.

Answer 1

Stimulates memory cells;

Secondary response, so antivenom / antibodies produced quicker;

Question 2

The box jellyfish produces a poison (venom) which enters the blood when a person is stung. A person who has been stung can be treated with an injection of antivenom. This antivenom is produced by injecting small amounts of venom from box jellyfish into sheep, then extracting antibodies from the sheeps’ blood. These antibodies are then injected into the person who has been stung.

(c) Suggest one possible problem in injecting people with antivenom made in this way.

Answer 2

Could transfer disease / Allergy / Immune response to antibodies
from animal;

Question 3

A test has been developed to determine if a person is infected with variant CJD (vCJD), the human form of BSE (mad cow disease). The test detects the protein which causes vCJD in a urine sample.

The test kit contains the following components.

(a) Complete the flow chart to describe how this test would be used.

Urine sample is added to well in test plate

↓

Plate is washed to remove unbound vCJD protein

Explain why this test would detect vCJD, but not other antigens in the urine.

Answer 3

add antibodies / enzyme;
wash to remove unbound antibodies;
add (colourless) solution;

antibodies specific / shape only fits one antigen;
other antigens different shape and would not bind to antibodies;

Question 4

Cells with BrdU in their DNA are detected using an anti-BrdU antibody with an enzyme attached.

Use your knowledge of the ELISA test to suggest and explain how the scientists identified the cells that have BrdU in their DNA.

Answer 4

  Add antibody (anti-BrdU with enzyme attached) to cells/DNA

OR

Add cells/DNA to antibody (anti-BrdU with enzyme attached);

2.   Wash (cells/DNA) to remove excess/unattached antibody

OR

Wash (immobilised antibody) to remove excess/unattached cells/DNA;

Allow ECF for absence of cells/DNA.

3.   Add substrate to cause colour change;