GenPharm International Inc. on Monday said it has produced thefirst transgenic dairy calf by introducing a gene for the milk-specific production of human lactoferrin (hLF).
GenPharm will begin breeding the 9-month-old bull calf inOctober or November to produce transgenic offspring that willproduce large quantities of hLF in cow milk, said Dr. JonathanMacQuitty, president and chief executive officer of theMountain View, Calif., company.
GenPharm will harvest the hLF from the milk and sell it as aningredient to manufacturers of orally consumed products, suchas infant formula and formulations intended to prevent orreduce bacterial infections in patients whose immune systemhas been weakened by chemotherapy or diseases such as AIDS.
The company's primary interest is to develop these hLFformulations, but it will develop other proteins that aredifficult to produce using other recombinant techniques,MacQuitty said, including small volume proteins that arepresent in blood plasma, such as blood factors, and largervolume products such as human serum albumin.
GenPharm's third priority is developing proteins that canimprove livestock's resistance to diseases (lactoferrin has arole in controlling certain cattle diseases such as mastitis) oralter the quality of milk by, for example, reducing lactose,changing fatty acid distribution or improving the compositionof milk for cheese producers.
The transgenic bull was produced at GenPharm's dairy in theNetherlands with assistance from the Dutch Ministry ofAgriculture. GenPharm is considering locating a dairy withtransgenic animals in the United States.
GenPharm plans to have a "small herd" of transgenic cows thatwill produce a sufficient quantity of hLF to begin clinicaltrials by 1993, MacQuitty said. The Food and DrugAdministration will base its approval on a demonstration ofthe safety of hLF and any accompanying impurities, he said.
Cattle are by far the most prolific producers of milk protein,which brings down the per-unit cost. But they are one of themore difficult mammalian species to work with and"lactoferrin is a complicated protein," said Dr. Darold McCalla,president of Granada BioSciences Inc., which is developinggenetically engineered beef cattle. "It's difficult to deal with,so it looks to me that this is a nice piece of work," he said.
Other companies are working with the milk systems of otherlivestock such as sheep, goats and pigs.
-- Kris Herbst BioWorld Washington Bureau
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