Transgenics is the burgeoning field of altering an animal's genetic makeup by inserting a foreign gene into an embryo. The promise for the technology is to slip a gene that produces a particular drug or protein into animals and turn them into living factories. And now, that's becoming a reality.
In the September issue of the scientific journal Bio/Technology, scientists report three major advances: In one, researchers at Pharmaceutical Proteins Ltd. in Edinburgh, Scotland, have produced five sheep that carry a gene for an enzyme that can prevent mucus buildup in the lungs of emphysema sufferers. These sheep secrete this enzyme in their milk. Another group, at GenPharm International in the Netherlands, engineered a transgenic calf whose female offspring will secrete the human protein lactoferrin in their milk. This protein has antibacterial properties and could be used in infant formulas and for patients with weakened immune systems.
Finally, scientists at Tufts University and Genzyme Corp. in Cambridge, Mass., report that they have produced and purified "economically significant levels" of the blood-clot-busting drug TPA--a human protein--in the milk of transgenic goats.