Antibodies are formed in the body when the body encounters foreign agents like viruses, bacteria and other germs. Soon after that our natural immune system produces antibodies that bind to the antigens and destroy them.
Antibodies have two very useful uniqueness. First, they are extremely specific; that is, each antibody binds to and attacks one particular antigen among millions of irrelevant sites. Secondly, some antibodies, once activated by the occurrence of a disease, continue to give resistance against that disease; examples are chicken pox and meseals occurring during early childhood that causes the production of antibodies against this disease. The second characteristic of antibodies makes it possible to develop vaccines.
Researchers have long dreamed of exploiting the specificity of antibodies for a variety of uses that require the targeting of drugs and other treatments to particular sites in the body. It is this use of antibodies as targeting devices that led to the concept of the magic bullet, a treatment that could effectively seek and destroy tumor cells and infectious agents wherever they resided.
It is the first peculiarity of antibodies, their specificity that makes monoclonal antibody technology so important. They can be used not only for therapeutic purposes but also in the diagnosis of a wide variety of illnesses and can detect the presence of drugs, viral and bacterial products, and other strange or abnormal substances in the blood.
PRODUCTION OF MONOCLONAL ANTIBODIES.
First a mouse o rat is inoculated with the antigen to which an antibody is desired. After the animal mounts an immune response to the antigen, its spleen, which houses antibody producing cells lymphocytes is removed and the spleen cells are fused on mass to a specialized myeloma cell line that no longer produces an antibody of its own. The resulting fused cells or hybridomas retain properties of both parents. They grow continuously and rapidly in culture like the myeloma cells, yet they produce antibodies specified by the lymphocyte from the immunized animals. Hundreds of hybrdomas can be produced from a single fusion experiment, and they can be systematically screened to identify those producing large amount of a desired antibody. Once identified this antibodies is present in limit less quantity.
MONOCLONAL ANTIBODY THERAPY
This involves the use of Monoclonal antibody to target the foreign proteins or cells. When these monoclonal antibodies (or mAb) bind to the antigen specifically the immune system of the body is triggered to produce antibodies against them. A large amount of research is done to monoclonals for numerous serious diseases such as rheumatoid arthritis, multiple sclerosis and different types of cancers.
There are a number of ways that mAbs can be used for therapy. For example: mAb therapy can be used to destroy malignant tumor cells and prevent tumor growth by blocking specific cell receptors.
• Radio immunotherapy (RIT); This involves the use of radioactively coupled murine antibodies against cellular antigens.
• Antibody-directed enzyme prodrug therapy (ADEPT) involves the application of cancer associated monoclonal antibodies which are linked to a drug-activating enzyme.
• Immunoliposomes : These are antibodies that are coupled with liposomes which in turn caries drugs or therapeutic nucleotides and when are bound to the monoclonal antibodies they are targeted against tumor cells.
USES OF MONOCLONAL ANTIBODIES
These have many uses in medical, academic and commercial uses . It has become a very important part of biotechnology. Following are its major uses.
• Antibodies are used in several diagnostic tests to detect small amounts of drugs, toxins or hormones, e.g. monoclonal antibodies are used in pregnancy test kits and in the diagnosis of AIDS by the ELISA test.
• Antibodies are used in the radioimmuno detection and radioimmuno therapy of cancer, and some new methods can even target only the cell membranes of cancerous cells. Drug that was developed by this technology for treating cancer is Ritoxin.
• Monoclonal antibodies can be used to treat viral diseases, usually considered "untreatable".
• Monoclonal antibodies can be used to classify strains of a single pathogen, e.g. Neisseria gonorrhoeae .
• During transplantation there is always the fear of organ rejection, but through monoclonal antibodies it can be overcome. OKT3, an antibody to the T3 antigen of T cells are widely used for this purpose.
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