Scientists claim to have engineered the world's first dairy cow to carry human genes. A single gene carrying an antibiotic normally found in human tears has been inserted into the eggs of Friesians and then implanted back to the mother cow. The gene, not naturally made in cows' milk, is produced in human tear glands and milk to fight infections.
Scientists hope to harvest the substance, called lactoferrin, from cows' milk to produce a cheap antibiotic for treating gastro-intestinal infections in humans and diseases such as mastitis in animals.
Because it is natural, the antibiotic should carry no harmful side-effects. In addition, bacteria are unlikely to acquire resistance, as has been the case with the widespread use of man-made antibiotics.
The Friesians, now about 10 months old, are the work of a team at the university of Leiden, Holland, led by Herman de Boer, professor of microbiology. A company, Gene Pharming Europe, has been set up to exploit the breakthrough.
Professor de Boer said yesterday that the novel technique they were using was leading a relatively high success rate in creating "transgenic" cows, an important consideration given that, unlike transgenic mice, cows take longer to develop.
The first milk carrying human antibiotic should be available some time next year, he said. News of the work, published in the industry magazine "Bio/Technology", comes as researchers at Tufts School of Veterinary Medicine, North Grafton, Massachusetts, have announced the development of transgenic goats, whose milk produces tissue plasminogen activator, a protein which dissolves blood clots and which is given to heart attack victims. The team believes the protein will work longer than any man-made equivalent.
At the same time, a team in Edinburgh has announced the production of five transgenic sheep, which may play a key role in the treatment of emphysema, the degenerative lung disease, and cystic fibrosis. They carry a human gene that controls the production of a protein called alpha-1-antitrypsin, a substance that blocks the breakdown of tissues in the lung and curbs the build-up of mucus.
About one in 1,000 people suffers from an inherited disease in which the body produces too little of that protein, leading to scarred and brittle lungs. In America some people are treated with supplements of the protein extracted from human blood, but the costs are high and only small amounts can be collected in that way.
The Edinburgh team, a collaboration between the company Pharmaceutical Proteins and the Agricultural and Food Research Council's institute of animal physiology and genetics research, believes the sheep may be the answer, because they produce high yields in their milk.
Martyn Breeze, marketing director at Pharmaceutical Proteins, said yesterday that the company hoped to have the anti-emphysema protein in mass production by the mid-1990s.
