Uses of monoclonal antibodiesSpec 5.22B
In short
Monoclonal antibodies bind to one specific antigen, so they can target particular molecules or cells. They are used in pregnancy tests to detect a hormone in urine, in diagnosis to show the position of blood clots or cancer cells, and in treatment to carry a drug directly to cancer cells, so fewer healthy cells are damaged.
Monoclonal antibodies bind to one specific antigen only, so they can be used to find or target particular molecules or cells.
- Pregnancy testing: a test stick contains monoclonal antibodies that bind to a hormone found in the urine of pregnant women. When the hormone is present, it binds to the antibodies and a coloured line appears, so the test is positive.
- Diagnosis: monoclonal antibodies carrying a label can be given to a patient. They bind to a specific antigen, so the label shows the position of blood clots or cancer cells.
- Treatment: a drug can be attached to a monoclonal antibody that binds to antigens on cancer cells. The antibody carries the drug directly to the cancer cells.
Advantages over drug and radiotherapy treatments
Drugs and radiotherapy can damage healthy cells as well as cancer cells, which causes side effects. Monoclonal antibodies target specific cells, so the cancer cells are attacked and fewer healthy cells are damaged.
The key word is 'specific'. Each monoclonal antibody binds to one antigen, and that is why it can target one type of cell.
Quick check
Why can antibiotics not be used to treat viral infections?
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Antibiotics inhibit cell processes in bacteria; viruses are not cells and reproduce inside host cells.
Triple only: why is an inoculating loop heated in a flame before use?
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To sterilise it by killing any microorganisms on it.
Triple only: in the core practical, what does a larger clear zone show?
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The substance is more effective at stopping bacteria growing.
Name the four stages in developing a new medicine in order.
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Discovery, development, preclinical testing, clinical testing.
Triple only, Higher tier: what is a hybridoma cell?
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A cell made by fusing an antibody-producing lymphocyte with a tumour cell; it divides and produces antibodies.
Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026