2.10 Monoclonal Antibodies Flashcards
What are antibodies?
Antibodies are small proteins produced by white blood cells or B-cells which help fight disease by binding on to antigens.
How do we make monoclonal antibodies? (4)
1) An animal, usually a mouse, is first injected with the antigen which you want to target.
2) The white blood cells in the mouse which recognise the antigen will then start to divide and produce antibodies against it.
3) A sample of blood is taken from the mouse and the cells producing the right antibody extracted from the sample.
4) The cells are fused with tumour cells (which can divide many times). They form something called a hybridoma. The resulting cells are placed in a culture medium and divide. This produces many cells that can produce lots of the antibody.
Describe how monoclonal antibodies can be used to identify whether someone has malaria (6)
1) Malaria is a disease caused by a pathogen called Plasmodium falciparum, which is found in the blood of infected people. The pathogen can be detected in a sample of blood using a diagnostic stick.
2) A sample of blood is added to one end of the stick, which contains monoclonal antibodies specific to the antigens on the surface of Plasmodium. These antigens are also labelled with a dye.
3) The blood sample and the antibodies move along the length of the stick towards a test strip.
4) Monoclonal antibodies which also recognise the Plasmodium antigens are stuck to the test strip.
5) If the pathogen is present in the blood sample, then the antibodies on the test strip and the antibodies which are stuck to the dye will bind to the pathogen’s antigens and the test strip will change colour.
6) If the pathogen is not present then the labelled monoclonal antibodies will not become stuck to the test strip and it won’t change colour.
What can we attack to the bottom of antibodies in order to locate or destroy specific types of cells? (3)
- Drugs
- Fluorescent proteins
- Radioactive material
What type of cell produces antibodies?
B-lymphocytes
Where are monoclonal antibodies made?
In a lab
How can monoclonal antibodies be used to target cancer cells?
Monoclonal antibodies can be designed to specifically target a certain cell-type in the body (e.g. just cancer cells). So you can use them to label specific cells for destruction by the immune system, or use them to target drugs to specific locations in the body.
What are cancer cells’ antigens called?
Tumour markers
Why are cancer cells’ antigens not recognised as ‘foreign’ by the body’s immune system?
Cancer cells are produced by the body
How can monoclonal antibodies be used to trigger a normal immune response to cancer cells? (3)
1) Monoclonal antibodies can be injected into a patient’s bloodstream.
2) The antibodies will then bind to the tumour makers on cancer cells in the patient’s body.
3) For some types of monoclonal antibody, this will result in the cancer cells being labelled, causing a normal immune response to the cells - the patient’s white blood cells will recognise the cancer cells as foreign and destroy them.
How can monoclonal antibodies be used to target drugs to cancer cells? (3)
1) An anti-cancer drug is attached to monoclonal antibodies. This might be a radioactive or toxic substance which stops cancer cells growing and dividing.
2) The antibodies are injected into the patient’s bloodstream and bind to the tumour markers on the cancer cells.
3) The drug kills the cancer cells but doesn’t kill any normal body cells near the tumour
Why are monoclonal antibodies better for targeting cancer cells rather than other cancer treatments?
1) Other cancer treatments, such as radiotherapy or chemotherapy, can affect normal host cells as well as killing cancer cells. This often leads to unpleasant side effects, such as hair loss and vomiting.
2) Since antibody-based drugs are targeted directly to the cancer cells, side effects tend to be less severe than for radiotherapy or chemotherapy treatments
