The dream antibiotic is one that would only kill the microbe and not harm the human body. Our bodies produce just such an antibiotic called antibodies (gif 2). They are proteins our white blood cells (B cells) produce that will only react with one antigen (antigen= a protein, sugar, etc. that our bodies do not recognise as being part of us) of a microbe. Unfortunately, purification of these very specific antibodies is very expensive and would require people to give large amounts of blood to get enough useful antibody for a particular microbial infection.
Other workers in the mid-1970's were able to make mouse antibodies in a test tube and to isolate the cells that make antibodies reactive with only one specific region of a microbial antigen. These antibodies are called monoclonal antibodies. Monoclonal antibodies are antibodies from only one antibody producing cell that makes only one particular antibody reactive with only one particular portion of an antigen. More very specific antibody could be made without the need to bleed people. These monoclonal antibodies are useful reagents to test people for certain diseases and are used very frequently in research.
Unfortunately, we can't receive too many injections of mouse antibodies to treat microbial diseases because our bodies recognize them as foreign. A very severe and life threatening immune reaction can occur. To avoid this complication other researchers have changed the genes in the mouse cells so that the antibodies that are made by these mouse cells are more like human antibodies (humanized monoclonal antibodies). Humanized monoclonal antibodies take longer to be rejected by the human body. Problem solved let's start giving people these antibodies and cure them of all sorts of illnesses. Wrong. The down side is once again the enormous cost of producing these antibodies. It could cost several thousand dollars for one treatment with these monoclonal antibodies.
There is still hope that this approach may work. Recently, Kevin J. Whaley of Johns Hopkins University reported the use of plantibodies from soybeans to prevent genital herpes infections in mice ( Zeitlin, L. . . . K.J. Whaley. 1998. A humanized monoclonal antibody produced in transgenic plants for immunoprotection of the vagina against genital herpes. Nature Biotechnology 16(December):136). Plantibodies are humanized monoclonal antibodies that are made in plants. Researchers have taken the humanized monoclonal antibody genes from the mouse cells and placed them in plants.
These plantibodies can be easily purified from the plant and are specifically
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