The insulin is then given to patients who need it. Researchers also have engineered E. coli to make proteins called interferons. These proteins are normally produced by body cells in response to viral infections. They have been tested against many diseases. See Interferon .
Many people suffer from diseases caused by genetic defects.
Using recombinant DNA techniques, scientists can test DNA isolated from cells of unborn babies to learn whether the babies will have a disease. Also, researchers have investigated methods of gene therapy in an effort to cure diseases. Doctors first used gene therapy to treat a patient in 1990. The patient suffered from a weak immune system. Since then, many clinical trials using gene therapy on people have been undertaken.