Antibodies in Biotechnology

Antibodies, which are described in the section on immunity, are good research tools because of their specificity to a particular protein. Antibodies can be so specific that they may even be able to distinguish between two proteins that differ by only one amino acid. Antibodies can be produced by injecting an antigen into a rabbit or chicken and after a period of time collect and purify the antibodies. The problem with this technique is that the animal produces antibodies not only to the antigen but also to pieces of the antigen.

Another way to produce antibodies is to take a cell that produces the antibody desired, combine it with a malignant myeloma cell and form a hybridoma. Because the hybridoma contains genes from a cancer cell, it will basically divide without aging. Again the antibody needs to be collected and purified.

Antibodies are used as very highly specific probes. Antibodies are used to monitor urine samples for prostate-specific antigens (PSA) that are diagnostic of prostate cancer. Antibodies are used in determining pregnancy or the Luteinizing hormone spurt just prior to ovulation. Biotechnologists use the antibodies to find a specific protein in the cell. If we add a small fluorescent molecule to the antibody, we can take a cell that has been exposed to a specific antibody, illuminate it and find the location of a specific protein. This technique has been used to locate the physical positions of enzymes associated with membranes so that scientists can better understand their function.