Antibodies are produced by immune systems to recognize and bind to foreign proteins. Monoclonal antibodies target only one specific protein and, because of this, can be designed to target particular cells for destruction by the immune system. Monoclonal antibody therapy may slow cancer growth, reduce the likelihood of organ rejection, help fight viral infections and reduce the effects of autoimmune diseases.
When the immune system is exposed to foreign proteins, the B-lymphocytes of the immune system produce antibodies that can bind specifically to those proteins. An antibody binds to the target antigen and acts as a sign for other immune cells, called phagocytes, to come and destroy the antigen. Different types of B-lymphocytes produce a range of antibodies, called polyclonal antibodies, which attach to different areas of the antigen. To target a specific type of antigen accurately for antibody therapy while avoiding destruction of healthy tissue, lots of identical antibodies known as monoclonal antibodies need to be used.
The first monoclonal antibodies were produced in 1975 by Georges Kohler and Cesar Milstein using immune system cells from a mouse that had previously been exposed to the desired antigen. The mouse cells were fused with cells that were cancerous and, thus, reproduced indefinitely. This unchecked growth produced a usable amount of genetically identical cells and identical monoclonal antibodies. The contemporary use of genetic engineering means cell lines can produce monoclonal antibodies that are part human and part mouse. This reduces the likelihood of a patient's own immune system recognizing the antibodies as foreign and attempting to destroy them.
Monoclonal antibody therapy reduces organ or graft rejection and can reduce effects of autoimmune disease by interfering with the patient's foreign protein recognition system. Monoclonal antibody therapy also has relevance in the field of virology. In that area, antibodies have the potential to be administered to patients to fight a specific viral infection.
Monoclonal antibody therapy may be prescribed as part of a cancer treatment regimen in which a particular monoclonal antibody can bind to cancer cells and mark them for phagocyte destruction. Monoclonal antibody therapy can also be designed to slow the growth of the cancer or stop the growth of blood vessels supplying the cancer with nutrients; it does this by blocking transmission of growth factors released by the cancer cells. Radiation therapy can also be delivered accurately to cancer cells, without harming nearby healthy cells, by attaching the radioactive substance to a cancer cell-specific antibody.