By Karen Pihl-Carey
Infigen Inc. said its herd of 40 cloned cattle will begin early next year producing therapeutic proteins to be used as therapies for genetic diseases.
Infigen Inc., of DeForest, Wis., created the cows through the same nuclear transfer cloning technology it used in 1997 to create Gene, the world's first cloned bull calf.
About 10 of the company's female cows are being showcased today at the World Dairy Exposition in Madison, Wis.
"We've brought a small group of these animals to the largest dairy show in the world to put them on exhibit to show people these animals are healthy, with normal growth rates, normal development," said Michael Bishop, Infigen's vice president of research, "and to show that this technology will be useful in the future."
The cattle at the exhibition are between 5- and 8-months old and all came from the same cell line. The entire herd comes from seven different cell lines. The first of the herd was born in November 1998.
Gene was produced from primordial embryonic stem cells obtained from a 30-day-old fetus in February 1997. He later fathered two calves, a male and female conceived through artificial insemination and in vitro fertilization. (See BioWorld Today, Aug. 8, 1997, p. 1.)
The hope is that genetically engineered animals will produce better products, such as milk. A farmer, for example, could select the best cows to produce mozzarella cheese, then clone these cows so the herd is known for the product it produces. But more importantly, these cows could produce pharmaceuticals, including human vaccines, plasma components and monoclonal antibodies, at less cost and in larger quantities than cell culture production methods.
"There's about 17 calves that are carrying the first commercial [pharmaceutical] product and many more to come," Bishop told BioWorld Today. "I think, right now, there are about 78 or 79 pregnancies in the pipeline for three different potential pharmaceutical products.
"These products will be able to fill a niche market known as orphan drugs that require complex proteins that might not be producible commercially today without the use of animals," he said.
Bishop wouldn't disclose specific products Infigen is developing in the cattle but said they will address genetic diseases. He expects the company will have about 150 cloned dairy and beef calves by this time next year.
Infigen was formed as a spin-off of ABS Global Inc., also of DeForest, in August 1997. The two companies formed a partnership in January 1998 with Pharming Holding NV, of Leiden, the Netherlands, to expand production herds of transgenic cattle for producing pharmaceuticals. A few days after the partnership was announced, Pharming formed a U.S. subsidiary, Pharming Healthcare Inc., to develop and commercialize blood-clotting proteins produced in the milk of transgenic animals. The products would help treat more than 55,000 hemophilia patients in North America, Europe and Japan, and possibly millions of others with traumatic injuries or those undergoing major surgery.
Human drugs, such as tPA, erythropoietin for anemia and blood clotting drugs for hemophilia, require modification that only cells of organisms like mammals can provide. They cannot be produced in bacteria, in the way that insulin and growth hormones are manufactured in E. coli. The cost is high to maintain mammalian cell cultures and they produce only small amounts of the drug. That is why Infigen is looking at transgenic animals to do the job.
"This nuclear transfer cloning technology, when you combine it with transgenic and cell culturing, provides a fast way of molecular farming," Bishop said.
Scientists achieve this by placing a foreign gene in the mammary gland of a cow. The cow then produces the protein through its milk, and scientists extract the protein and convert it into human pharmaceuticals. Cloned offspring of the cow can then produce the protein on their own.
The cloned calves are created through a nuclear transfer process in which a gene is introduced into cultured female bovine cells from a fetus. Cells that take up the transgene are isolated and their nuclei fused to cow oocytes (eggs). The nuclei are then removed. The resulting transgenic embryos are implanted into a foster mother and carried to term.
In January 1999, Infigen partnered with Imutran Ltd., a subsidiary of Novartis Pharma AG, to enhance the quality of transgenic pig organs being developed for transplantation into humans. By modifying the DNA of pig cells, the company will add or remove specific proteins, making the pig more physiologically compatible with humans. There are more than 60,000 Americans awaiting a transplant and 10 of them die each day waiting.
The company's proprietary genomic databases also will help develop technology for skin regeneration and replacement, as well as help produce plants with particular genes to allow animals to self-vaccinate themselves against disease.
"We've been working very hard molecularly doing a lot of gene expression mapping and building databases that can be mined to find specific genes that are specific to certain cell types in animals," Bishop said. "And we believe that information will be useful in the future for people involved in cell therapy and tissue engineering."