GenPharm International Inc.'s transgenic bull, Herman, hassired eight transgenic calves that carry the gene for humanlactoferrin, an antibacterial protein normally produced inhuman milk.
The companyUs chief executive officer, Jonathan MacQuitty,announced Monday at the Hambrecht & Quist Annual LifeSciences Conference in San Francisco that this is "the firstscientific proof that transgenesis in dairy cattle is feasible."
In August 1991, GenPharm of Mountain View, Calif.,microinjected a gene for human lactoferrin into Herman, then acalf, at the companyUs dairy facility in the Netherlands. Heiferswere then artificially inseminated with semen from Herman,resulting in 55 pregnancies. Eighteen animals have been born,of which eight are transgenic.
MacQuitty told BioWorld that the company expects to get initiallactation samples by the third quarter of next year, and willthen proceed to do lab tests and develop a commercial herd. Hesaid about 200 transgenic cows will be required tocommercially produce human lactoferrin. The protein will beharvested from the milk and sold to manufacturers of orallyconsumed products, such as infant formula and formulationsintended to prevent or reduce bacterial infections in patientswhose immune systems have been weakened by chemotherapyor diseases such as AIDS.
GenPharm is making a range of human milk proteins, includinghuman lysozyme and human collagen. MacQuitty said humanDNA encoding for each of these proteins has been combinedwith the regulatory control region and each of the constructshas been microinjected into fertilized eggs of mice. He said theDNA has been passed on properly from one generation to thenext and has been produced in large quantities (50micrograms/milliliter).
GenPharm is the only company to produce transgenic dairycattle. Three other companies are working oncommercialization of pharmaceuticals from the milk of sheepand goats and the blood of pigs. Pharmaceutical Proteins Ltd. ofEdinburgh, Scotland, has expressed human alpha-1-antitrypsinin the milk of ewes. Genzyme Transgenics, a spinoff of GenzymeCorp., has produced several different human enzymes inanimals, including tissue plasminogen activator in rabbits andgoats, and anti-thrombin III in mice and goats. And DNX Corp.has produced human hemoglobin in swine. DNX dropped itsprogram to develop recombinant human hemoglobin fromtransgenic pigs last October.
-- Brenda Sandburg News Editor
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