What monoclonal antibodies are
- Monoclonal antibodies are identical antibodies produced from a single clone of cells.
- They are specific to one binding site on one protein antigen, so they can target a particular chemical or specific cells in the body.
How they are made
- A mouse is injected with an antigen, which stimulates its lymphocytes (a type of white blood cell) to make the matching antibody.
- The lymphocytes are combined with a particular kind of tumour cell to make a cell called a hybridoma.
- The hybridoma can both divide (like the tumour cell) and make the antibody (like the lymphocyte).
- Single hybridoma cells are cloned to produce many identical cells that all make the same antibody. The antibodies are then collected and purified.
Uses of monoclonal antibodies
- Pregnancy tests: antibodies stick to the hormone HCG, found in the urine of pregnant women.
- Diagnosis in hospitals and laboratories, for example measuring hormone levels or detecting pathogens.
- Research: antibodies with a fluorescent dye attached locate or identify specific molecules in cells or tissues.
- Treating diseases such as cancer: an antibody can carry a radioactive substance, a toxic drug or a chemical that stops cells growing and dividing, delivering it to the cancer cells without harming other cells.
Advantages and disadvantages
- Advantages: they bind only to specific cells, so healthy cells are not affected; they can be used to treat a wide range of conditions.
- Disadvantages: they have caused more side effects than expected, and they are expensive to develop. They are not yet as widely used as scientists hoped.
Key terms
- Monoclonal antibodies
- Identical antibodies made from a single clone of cells, all specific to the same antigen.
- Lymphocyte
- A white blood cell that makes antibodies.
- Hybridoma
- A cell made by fusing a lymphocyte with a tumour cell; it divides and makes one kind of antibody.
- Clone
- A group of genetically identical cells.
- Antigen
- A protein that an antibody binds to.
- HCG
- A hormone found in the urine of pregnant women, detected by pregnancy tests.
- Fluorescent dye
- A chemical that glows, used to show where antibodies have bound.