Monoclonal Antibodies and Cancer Treatment

What are Monoclonal Antibodies?

Monoclonal antibodies (mAb or moAb) are laboratory-made biomolecules. They have a great degree of specificity, that is, the ability to recognize a specific molecule. The human body naturally produces antibodies as part of its immune system. In fact, antibodies are produced as a self-defense mechanism as soon as an invader (a germ for example) enters the body. What is particularly clever about them is that they are extremely specific - each one is able to bind to a particular invader - known as an antigen (it stands for antibody generator).

Monoclonal antibodies made in a laboratory setting can be produced for a variety of reasons: for analysis, for testing, for diagnosing diseases (because they bind to one type of bacterium or virus) and for cancer treatment (if they are carefully crafted to target specific cancer cells). Technology is available today to create virtually any type of monoclonal antibody for almost any given substance. MoAbs have become of paramount importance in biochemistry, molecular biology and medicine.

How are Monoclonal Antibodies Made?

Monoclonal antibodies are made when a tumor cell, that is able to duplicate indefinitely, is fused with mammalian cells that produce antibodies. This cell fusion is called a "hybridoma," and it is a 24 '"hour antibody factory. It consistently pumps out monoclonal antibodies. The term monoclonal derives from the fact that the antibodies come from one parent source - the hybridoma.

Originally MoAbs were made by fusing myeloma cells, a cancer that can grow in the bone marrow, with the spleen cells from a mouse that has been injected with the desired antigen (that is the target molecule of the antibody). These fused hybrid cells - because they are derived from cancer cells - can grow indefinitely. There were problems initially when human bodies rejected bits of mouse being placed inside them, but the technology has been improved to 'humanise' the antibodies.

The mixture of cells is diluted and clones of single cells are grown on micro wells. The antibodies derived from these are tested (using ELISA for example) and the most productive wells are selected and grown to a high volume level. Finally, antibodies are purified by eliminating all undesired material.

Using Monoclonal Antibodies for Cancer Treatment

Since these molecules are very specific they can be used to target specific cells within the body. In 1997, The Food and Drug Administration (FDA) approved the first monoclonal antibody for cancer treatment. The great deal of specificity of these molecules can be used for a variety of purposes in cancer treatment. They are able to recognise a specific protein on a cancer cell and bind to it. This either triggers the body's own immune system to deal with the tumor or releases drugs that have been attached to the antibody.

Many monoclonal antibody therapies today are still experimental treatments and caution is exercised when they are being considered. However, they have the potential of tackling and dispatching hundreds of different diseases, not just cancers