3.2 Monoclonal antibodies Flashcards
Monoclonal antibodies
Monoclonal antibodies are produced from clones (genetically identical copies) of cells (often white blood cells). They are all identical and are complementary to one type of antigen.
Monoclonal antibodies are specific to one binding site on one protein antigen.
Producing monoclonal antibodies
The lymphocytes are combined with a particular type of tumour cell to make a hybridoma cell.
Tumour cells can divide repeatedly which is why they are used.
The hybridoma cell can both divide and produce the antibody.
Single hybridoma cells are cloned, resulting in many divisions, making high quantities of identical cells that all produce the same antibody.
A large amount of the antibody can be collected and purified ready for use.
Pregnancy tests of monoclonal antibodies
Pregnant women produce a hormone called Human chorionic gonadotropin (HCG).
As urine passes through the reaction zone, HCG hormone binds to the mobile HCG antibody in the reaction zone.
The HCG hormone binds to the immobilised HCG antibodies in the result zone.
The other antibodies which do not attach to the HCG bind to the antibodies in the control zone and a dye appears in both control and result zone to show a positive result.
If a person is not pregnant, the free antibody moves through the reaction zone, and instead binds to the fixed antibody in the control zone, causing a colour change here.
Diagnose of disease of monoclonal antibodies
The monoclonal antibodies are specific to antigens found on the surface of pathogens, blood clots or cancer cells. They also contain markers that help the doctors to find the location of them. It is used in the test for prostate cancer.
Measuring and monitoring of monoclonal antibodies
Since monoclonal antibodies are specific to one antigen, they can be designed to identify specific chemicals in the blood.
For example, they can:
Identify particular molecules in a tissue or cell by binding to them with a fluorescent dye. Areas in the body with lots of these molecules can be highlighted using the dye.
Identify the levels of hormones in the blood.
Be used to test blood samples for pathogens, such as HIV.
Research of monoclonal antibodies
Monoclonal antibodies with a fluorescent dye attached can be used by scientists to detect specific molecules in a cell or tissue.
Treating diseases using monoclonal antibodies.
Monoclonal antibodies can be produced to bind to target cells in the body, e.g. cancer cells.
We can attach anti-cancer drugs to the monoclonal antibodies. When they bind to the cancer cells, they can deliver the drugs directly to the tumours.
This is an effective cancer treatment because the antibodies cannot bind to or damage any normal human body cells (because normal cells will not have the complementary antigens).
Advantages of monoclonal antibodies
They only bind to specific molecules on diseased or damaged cells - they do not affect healthy cells.
Tried and tested method of treating conditions so is reliable.
Disadvantages of monoclonal antibodies
Caused more side effects than first expected. The use of mice antibodies caused complications. Now humanised antibodies are being developed.
It is an expensive procedure at the moment.
Producing specific monoclonal antibodies is difficult.
