By Lisa Seachrist
When sheep clone Dolly made a splash in February, the Scottish scientists who produced her emphasized that, while cloning humans was clearly unethical, the good that could come from creating better breeds of livestock and animals capable of producing pharmaceutical proteins spurred their research forward.
Genzyme Transgenics Corp., of Framingham, Mass., and Advanced Cell Technology Inc., of Worcester, Mass., have teamed up in a $10 million collaboration to harness the power of genetic engineering and cloning technologies to create cloned cows capable of producing human serum albumin in their milk.
The five-year deal calls for Genzyme Transgenics to pay $10 million to Advanced Cell Technology in return for its proprietary bovine cloning techniques. Genzyme Transgenics will provide genetic engineering experience
"We are very excited about the opportunity to work with Advanced Cell Technologies; it gives us the opportunity to optimize transgenic technology," said Patricia Dimond, director of communications for Genzyme Transgenics. "To produce enough albumin protein to have therapeutic value, we need to go to the cow."
Plasma-Derived Albumin Carries Risk
Human serum albumin is used to keep the correct balance of protein and fluids in the blood of patients who are suffering from burns, shock or malnutrition, or who are undergoing major surgery. Every year, approximately 440 metric tons of albumin are used worldwide. That albumin, which comes from pooled plasma, represents a $1.5 billion market.
The companies estimate that a single transgenic dairy cow could generate 80 kg of recombinant human albumin each year. In addition, the recombinant protein wouldn't carry the infection risks of plasma products.
"Basically, should the cloning work, this provides a more efficient way to create a transgenic animal," said Cheryl Greenhouse, senior public relations associate for Genzyme Corp., which owns 43 percent of Genzyme Transgenics.
Genzyme Transgenics has produced several transgenic goats capable of producing human proteins in their milk. Three individual goats produced enough Antithrombin III for the company to complete Phase II studies of the protein.
Nevertheless, traditional transgenic technology is wrought with inefficiencies. It involves injecting a human gene of interest into fertilized eggs, and of the animals born, only five to 10 percent will harbor the gene. In addition, the method produces both males and females. It takes several generations to develop a female herd large enough to produce adequate levels of protein.
Advanced Cell Technology's cloning methods involve introducing the gene into fetal fibroblast cells in culture. The nuclei of those cells are then transferred into enucleated eggs. The resulting embryos are implanted into surrogate mothers. All of the cows born will be female. And the process essentially creates a herd in one generation.
"Cloning will allow us to skip a lot of time-consuming steps," Dimond said.
Several cows already are pregnant with embryos carrying a marker in order for Advanced Cell Technology to prove the procedure works. After proving the concept, the two companies will work toward producing a herd of cloned transgenic cows capable of producing albumin.
"When Dolly was announced, she was important because she was produced from an adult cell," Dimond said. "While that is biologically interesting, from the perspective of creating transgenic animals it is not that important. The ability to create a stable cell line of nuclei offers an nearly endless supply of animals." *