Added: 02/16/2006 |
The Role of Antibodies in a Person's BodyTherapeutic antibodies are laboratory-engineered substances that recognize and bind onto a protein on the surface of a cell. Each therapeutic antibody recognizes a different protein, or antigen, and in general can be used alone, in combination with chemotherapy or as a carrier of substances such as toxins or radiation.
After binding to the targeted site, the therapeutic antibody can block the growth of the tumor and/or recruit the body's immune system to attack the target, and can also sensitize a cancer cell to chemotherapy.
What does it mean when a therapeutic antibody is referred to as "naked" or "unlabeled" The term "naked" or "unlabeled" is used when a therapeutic antibody is not a carrier of substances such as toxins or radiation. Sometimes naked or unlabeled antibodies are used because they affix themselves to specific antigens on cancer cells, marking the cancer cell for destruction by the immune system.
Other naked or unlabeled therapeutic antibodies are used because they attach to certain sites, called receptors, on cancer cells where they signal cancer cells to die (apoptosis) or they can work by blocking other molecules that stimulate the cancer cells' growth from binding to the cancer cell.
Blocking the other molecules from attaching there is how therapeutic antibodies prevent rapid growth of the cancer cells. Naked or unlabeled antibodies also can be used with other therapies such as chemotherapy.
Another important biological therapy involves antibodies against cancer cells or cancer-associated targets. Monoclonal antibodies are artificial antibodies against a particular target (the "antigen") and are produced in the laboratory.
The original method involved hybridome cells (a fusion of two different types of cells) that acted as factories of antibody production. A major advance in this field was the ability to convert these antibodies, which originally were made from mouse hybridomes, to "humanized" antibodies that more closely resemble our natural antibodies.
Even newer techniques can be used to generate human antibodies from genetically engineered mice or bacteria? containing human antibody genes. Monoclonal antibodies have been widely used in scientific studies of cancer, as well as in cancer diagnosis.
As therapy for cancer, monoclonal antibodies can be injected into patients to seek out the cancer cells, potentially leading to demolition of cancer cell activities or to increase of the immune response against the cancer. This strategy has been of great interest since the original invention of monoclonal antibodies in the 1970s. After many years of clinical testing, researchers have proven that improved monoclonal antibodies can be used effectively to help treat certain cancers.
Two types of monoclonal antibodies are used in cancer treatments: naked monoclonal antibodies are those without any drug or radioactive material attached to them, and conjugated monoclonal antibodies are those joined to a chemotherapy drug, radioactive particle, or a toxin (a substance that poisons cells).
Naked antibodies attach themselves to specific antigens on cancer cells. They can be used in different ways. Some mark the cancer cell for the immune system to destroy it. Others attach to certain antigen sites, called receptors, where other molecules that stimulate the cancer cells' growth might otherwise attach.
By blocking the other molecules from attaching there, the monoclonal antibodies prevent the cancer cells from growing rapidly. Conjugated monoclonal antibodies are joined to drugs, toxins, or radioactive atoms. They are used as delivery vehicles to take those substances directly to the cancer cells.
It delivers the toxic substance to where it is needed most, minimizing damage to normal cells in other parts of the body. But conjugated antibodies still generally cause more side effects than naked antibodies do. The actual effects depend on which type of substance they're attached to.
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