1) Antibodies and Monoclonal Antibodies.
A healthy body deals with the threat of invading bacteria, viruses and other foreign substances by producing antibodies. These essential body chemicals seek out and form a close bond with the invading organisms as a prerequisite to their ultimate elimination. Apart from defending the body against attack, antibodies have been much used for basic research into the immune system and as a means of measuring the concentration of small amounts of substances. For such analytical purposes antibodies have traditionally been produced by injecting animals with the substance under investigation. Blood samples are later taken and contain antibodies that can be used to identify and measure the substance originally injected. But occasional scientific reports show that antibodies can be produced in vitro. In 1974, researchers at Japan's Osaka University Medical School described how human tonsil tissue could be used to produce antibodies in response to foreign substances.(47) The tissue is obtained from therapeutic tonsilectomy:
"Since it is very easy to obtain large numbers of human Iymphocytes from tonsils and they contain complete sets of cells necessary for antibody formation in vitro, tonsil Iymphocytes could be very useful for the investigation of the immunologic phenomena in humans."
Recently there has been great interest in monoclonal antibodies. It is in the nature of cancer cells to reproduce themselves indefinitely but this can be turned to advantage by combining them with other cells which produce antibodies. The combined cell system is called a hybridoma and continues to produce antibodies indefinitely. Since the antibodies are of the same type and come from the same original cell, they are called monoclonal antibodies.
Although the two cell types that form the hybridoma often originate from animals, there are advantages in using human tissues. This is because monoclonal antibodies may have therapeutic applications in addition to their more familiar diagnostic role. Used therapeutically, monoclonal antibodies are administered to people, and if derived from animals, present a high risk of allergic reactions. Symptoms include fever, rashes, vomiting, rapid heart beat and difficulty breathing.(48) Furthermore the human body sees them as "invaders" and acts to reduce their effectiveness. The solution is to develop monoclonal antibodies entirely of human origin: in other words human cancer cells would be linked to human antibody forming cells.
The requirement for human antibody forrning cells has given scientists the incentive to produce antibodies in vitro because the traditional method of antibody production - the deliberate injection of foreign substances into a living being - would be regarded as unethical in people. Tonsils, spleens and Iymph nodes, obtained surgically, are valuable sources of Iymphocytes which can be used to produce human antibodies in vitro. But by far the most convenient source of Iymphocytes is human blood.(48)
A possible therapeutic application of monoclonal antibodies is in cancer research where they may have value as a less toxic form of treatment. Researchers at Japan's Kyushu University and the National Kyushu Cancer Center Hospital have produced human monoclonal antibodies that lock onto breast cancer cells in sick patients. In this case the hybridoma was made up of Iymphocytes from the Iymph nodes of breast cancer patients and from human cancer cells.(49)
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