Scientists can 'knock out' major cow's milk allergen

Kiwi scientists have discovered a new way to knock out a major milk allergen by editing a cow's genome.

Their findings, just published in the journal Scientific Reports, could point the way to speciality products for those who suffer from cow's milk allergies – particularly young children.

Cow's milk remains one of the most common causes of food allergy in infants, affecting one in 50 children, and in a small number of people symptoms can persist into adulthood.

Symptoms can range from mild to life-threatening.

In the new study, AgResearch scientists focused on the allergen beta-lactoglobulin (BLG), which forms a large part of the allergic reactions two to three per cent of infants have to cow's milk.

"What we have demonstrated is that we can eliminate a major allergen like beta-lactoglobulin from the cow's milk, and do so safely," AgResearch senior scientist Dr Gotz Laible said.

"We have achieved this by making a change in the genome that mimics what is potentially a naturally occurring mutation.

"We've also done it in a way that avoids the risk of introducing a new allergen to the milk in the process."

Genome editing is a technology being pursued in science around the world for the purpose of genetic improvement, and the possibilities it may create for human health.

In the study, modified embryos were transferred into surrogate cows, from which three calves were born.

Sequencing results showed how the change had effectively wiped out production of BLG.

Laible said more research is still needed around other allergens in milk that may affect people, aside from BLG, and how they could also be addressed.

"There is also research happening elsewhere in the world in relation to the knock-out of milk allergens and we are keen to see how our work lines up alongside what is being done by other scientists."

AgResearch worked with US-based biotechnology company Recombinetics in the project.

It followed another study led by Laible that targeted the same effect in Daisy - the first cow in the world to produce high protein milk that may also be hypo-allergenic.