Antibody Therapy for Prostate Cancer
Scientists in the US led by Dr. Mark Greene of the University of Pennsylvania School of Medicine have developed a monoclonal antibody that they hope will become a successful therapeutic agent against prostate cancer. Every year thousands of men die from aggressive forms of this disease. This research holds out hope for those affected although it will be some time before clinical trials will be carried out.
When we become infected by foreign cells such as bacteria or viruses or cancer cells one very important means of defense that we can utilize is to produce antibodies. All cells have proteins on their surfaces known as antigens. When foreign cells enter our bodies the antigens are recognized as foreign by our immune system and B Lymphocytes are prompted to produce antibodies. Once antibodies are formed they act by attaching and binding to the antigens on the surface of the invading cell. This ultimately leads to the destruction of the cell and the removal of the infection or cancer cells. Antibodies are a very powerful weapon in our fight against disease.
There are two significant characteristics of antibodies that we can exploit in the treatment of disease. One is that antibodies are totally specific. For example if we contract an infection such as rubella we will produce an antibody specifically targeted to the rubella virus. The second characteristic is that antibodies remain in our bodies after an infection has been cleared thereby conferring protection into the future against that disease.
It is these characteristics that have led to the development of vaccine technology. Pharmaceutical companies take pathological organisms and treat them so that they cannot cause infection. These inactive organisms make up the main component of a vaccine. When a vaccine is administered our immune system recognizes the antigen, antibody is produced and we become immune to future infection.
The cells which produce antibodies are B Lymphocytes, which are white blood cells. Scientists can isolate and clone B lymphocytes to produce antibodies in laboratory conditions. These antibodies can then be used therapeutically to treat infection or cancer. The antibodies produced will be either polyclonal or monoclonal. Polyclonal antibodies are produced from several cell lines. Monoclonal antibodies are produced from just one cell line. To produce a monoclonal antibody a B Lymphocyte is fused with a tumor cell. The fused cell is known as a hybridoma and it has the capability of reproducing endlessly. This technology allows scientists to create unlimited and large quantities of very specific antibody which can be used to treat disease very effectively. One of the major advantages of the use of monoclonal antibodies is its absolute specificity. It targets a cancer cell directly with with very few side effects for the patient.
Antibodies are already being used to tackle diseases such as lymphoma and breast cancer. Up to now there has been no successful antibody therapy for prostate cancer. Dr Greenes research team has produced an antibody called F77 which looks very promising. Despite the research being at a very early stage, it raises the prospect of an effective treatment for advanced prostate cancer for the first time.