Allergy-free milk on the way

The cow is called Daisy and is about 11-months-old.
The cow is called Daisy and is about 11-months-old.

Allergy-free milk for children is a step closer after New Zealand scientists made a world-first breakthrough using a genetically-modified cloned cow.

The country's largest crown research institute AgResearch said it had bred the first cow in the world to produce high-protein milk with greatly reduced amounts of a protein believed to be the leading cause of milk allergies in children.

"It's a very significant result," the institute's research director Dr Warren McNabb said. He was unable to say how much the breakthrough could mean financially for New Zealand, or how much the project had cost to date.

It has been under way since 2006, and funded by the Business, Innovation and Employment Ministry and AgResearch.

The question of whether the milk was hypoallergenic (low allergy), and could eventually be produced and marketed as such, was the subject of further experiments, he said.

The cow is called Daisy and is about 11-months-old.

She has a mysterious missing tail that AgResearch says it is investigating. It expects to have an answer in a couple of weeks, but does not believe at this stage the lack of a tail is linked to genetic modification.

Before the milk could be tasted by humans, tested in clinical trials on humans or produced commercially, New Zealand's genetic modification policies would need to change, McNabb said.

Currently New Zealand has restrictive policies, with strict rules on genetic modification including containment provisions for research.

"It's going to come down to what this country decides. It's more of a social issue than a scientific one."

Working in containment at Ruakura in Hamilton, the scientists, led by Dr Goetz Laible, used scientific processes to greatly reduce the amount of a milk protein known as beta-lactoglobulin (BLG) in Daisy's milk.

BLG is a milk whey component believed to be the main cause of allergic reactions to cows' milk particularly in infants and children, McNabb said. It is not in breast milk.

The research results publish today in a prestigious American scientific journal, Proceedings of the National Academy of Sciences. McNabb said AgResearch achieved the results by working successfully with mice first.

It then produced Daisy, a female calf genetically engineered to express two micro RNAs (short ribonucleic acid molecules).

Using a technique called "RNA interference", the micro RNAs "knocked-down" the expression of the BLG protein.

AgResearch's Dr Stefan Wagner said Daisy was created using similar technology to that used to create the world-famous cloned sheep Dolly.

He confirmed the cow Daisy was "all cow" without any components of other animals. McNabb said the milk research was still in its early days.

The initial results came from inducing Daisy to milk, as she was too young to produce milk naturally.

She had produced about a cup of milk over five consecutive days, which was "more than enough" to do the analysis and allergenicity tests.

Next steps in the project include breeding from Daisy, possibly next year, and for Daisy to start milking naturally so further tests could be done.

"If we can see similar results in another lactation, we suddenly have cows' milk without what everyone believes is the main allergen in cow's milk," McNabb said.

There were also plans to produce a few more cows the same as Daisy by the beginning of next year. McNabb said possible commercial production of hypoallergenic milk was a long way off.

"If this milk is to be hypoallergenic, as we suspect it will be, then we've got to get over the hurdle of social acceptance of this type of technology before you can then apply it in the national herd.

"It's going to come down to what this country decides. It's more of a social issue than a scientific one."

The successful research team comprised co-authors Anower Jabed, Stefan Wagner, Judi McCracken, David Wells and Goetz Laible.

Dr Mike Boland, principal scientist and executive officer at the Massey University-based Riddett Institute, said the production of a viable calf that did not produce BLG was scientifically very interesting and the work was exciting.

While the composition of milk from the experimental animal had been shown to be quite unusual it had to be viewed with caution.

That was because it was artificially produced - induced by hormones - rather than from natural lactation. It also remained to be seen whether the animal was able to breed, Boland said.

A niche opportunity must exist for milk such as that produced by Daisy, for use in things such as hypoallergenic infant formulas.

But BLG was important for muscle metabolism, which was why whey powder was favoured by sports people and body builders, and is the source of gelling functionality in whey products.

"And, of course, most people are not allergic to cows' milk. There is therefore not a case for getting rid of beta-lactoglobulin from all milk."

Professor Bruce Whitelaw, professor of animal biotechnology at the University of Edinburgh, said the research was notable because it was one of the few RNA interference success stories in mammals. It offered a good example of how those technologies could be used to provide alternative strategies to current manufacturing processes.

The study was a milestone in the field, although time would tell how widely applicable RNA interference would be in GM livestock.

Waikato Times