3.2.2 Uses of Monoclonal Antibodies

Examples of the uses of monoclonal antibodies include in pregnancy tests, in laboratories to measure the levels of hormones or chemicals, in research and in the treatment of some diseases.

Pregnancy tests

A hormone called human chorionic gonadotrophin (hCG) is present in the urine of women who are pregnant.

• There are two sections of the stick.
• The first section has mobile antibodies complementary to the hCG hormone- these antibodies are also attached to blue beads.
• The second section has stationary antibodies complementary to the hCG hormone which are stuck down to the stick.
• The individual urinates on the first section, and if hCG is present it binds to the mobile antibodies attached to blue beads to form hCG/antibody complexes.
• They are carried in the flow of liquid to the second section.
• The stationary antibodies then bind to the HCG/antibody complexes.
• As they are each bound to a blue bead, results in a blue line.
• This indicates that you are pregnant.

In laboratories to measure and monitor

• They can be used to measure and monitor levels of hormones or chemicals in the blood.
• The monoclonal antibodies are modified so that they will bind to the molecule you are looking for.
• The antibodies are also bound to a fluorescent dye.
• If the molecules are in the sample then the antibodies bind to it, and the dye can be observed.
• An example is screening donated blood for HIV infections.

In research to find or identify certain molecules on a cell or tissue

• The same method as above is applied, and scientists look for a build up of the fluorescence.

In the treatment of disease, e.g. cancer

Cancer cells have antigens on their cell membranes known as tumour markers (not found on normal body cells), which can be targeted. There are three main ways to treat cancers using monoclonal antibodies.

Producing monoclonal antibodies that bind to the tumour markers in order to stimulate the immune system to attack the cell.

Using monoclonal antibodies to bind to receptor sites on the cell surface membrane of the cancer cells. This means growth-stimulating molecules cannot bind, stopping the cell from dividing.

Using monoclonal antibodies to transport toxic drugs, chemicals or radioactive substances as they can only bind to cancer cells.

Advantages of using monoclonal antibodies	Disadvantages of using monoclonal Antibodies
They only bind to specific cells, meaning healthy cells are not affected.	It is difficult to attach monoclonal antibodies to drugs.
They can be engineered to treat many different conditions.	They are expensive to develop.
We are now able to produce mouse-human hybrid cells to reduce the chance of triggering an immune	As they were produced from mice lymphocytes, they often triggered an immune response when used in