These are stirring great interest among researchers. The surfaces of viruses, bacteria and even normal cells contain specific molecules that are called antigens. When they enter the body, these molecules trigger certain blood cells to produce antibodies, proteins that lock onto the antigens and render them harmless. All vaccines are made from antigens that induce the formation of antibodies in advance to ward off infectious diseases.
First, researchers inject a mouse with an antigen, for example, a human cancer cell. The mouse then makes antibodies to different components of the cancer cell, including abnormal proteins associated with cancer itself. The investigator removes the mouse's spleen, where much of the antibody production occurs, and extracts its cells. They then fuse these cells with cancer cells from another mouse with myeloma. These tumor cells are used because they are immortal: they will continue to divide ad infinitum and make the fused hybrid do the same. Finally, the scientists select the hybrid cells that are producing the particular antibodies they want and encourage them to reproduce, or clone, in separate tissue cultures. All of this is done in the laboratory.
The products are called monoclonal antibodies because each come from a single line, or clone, of cells.
If special antigens can be found on cancer cells that are not present on normal cells, the lab-produced antibodies would home in on tumors like heat-seeking missiles while ignoring normal tissue. These antibodies could be tagged with radioactive substances or chemicals to carry lethal doses directly to cancer cells while bypassing normal cells. One application currently being tried for pancreas cancer is arming these monoclonal antibodies with the patient's own white blood cells to kill the malignant cells. The entire treatment is done in one day with usually no side effects for this normally fatal disease.
Also, they have the potential of causing a revolution in diagnosis. Doctors can tag these antibodies with radioisotopes and scan the whole body for individual clusters of cancer cells that cannot be detected with current methods. While today they have been developed for only a few of the many types of cancer, and what has been developed is in extremely short supply compared to the demand, the entire concept of monoclonal antibodies is mind boggling and the potential is enormous.