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 (proteins found on the surface of pathogens).
Monoclonal antibodies are specific to one binding site on one protein antigen (on the surface of cells).
This means that monoclonal antibodies target specific chemicals or cells in the body.
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)
Reaction zone - The reaction zone contains a type of antibody that recognizes and binds to hCG molecules.
Result zone - hCG bound to the free antibody (and by extension the dye enzyme) enters the test site. Here, the hCG-free antibody complex will bind to another fixed antibody using the hCG. This will bring the enzyme (attached to the complex) close to a dye substrate – a reaction occurs, causing a colour change.
Control zone - There is fixed antibody in the control site. This will bind to any free antibody (not bound to hCG), and cause a colour change here.
If a person is not pregnant, the free antibody moves through the test site, and instead binds to the fixed antibody in the control site, causing a colour change here.
If a person is pregnant, the hCG-free antibody complex will form in the reaction site, and this complex binds in the test site, causing a colour change here. Some free antibody will still pass to the control site, so you will see two stripes.
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.
Highly specific so can be produced to treat a range of conditions.
Hoped to be a cheaper procedure and tried and tested method of treating conditions.
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.
