Transgenic risk

a project to develop peas with pest-resistance induced through genetic changes has been given up after tests on mice showed allergic lung damage.

Scientists at Australia's Common wealth Scientific and Industrial Research Organisation had taken a gene from the bean plant and transferred it into peas. The gene expresses a protein -- alpha-amylase inhibitor-1 -- that can kill pea weevil (Bruchus pisorum), a beetle that devastates pea crops worldwide. The researchers found the protein the ene expressed in the pea, has subtle structural differences compared to the one produced in beans. These differences, they feel, may be responsible for the allergic reaction observed in mice. The findings appeared in the Journal of Agricultural and Food Chemistry (Vol 53, No 23).

The research underlines the need to evaluate each new transgenic crop, says Paul Foster of the Australian National University in Canberra, who led the work. According to Jeremy Tager, Greenpeace Australia's campaigner on genetic engineering, the results indicate the potential for unintended changes in the structure of transferred proteins.

Foster and his team found mice that ate transgenic peas developed antibodies against the protein. Some of these mice were later exposed to the purified protein, either through injection into the blood, or by putting the protein into their airways. This approach is a standard "multiple immune challenge" procedure designed to determine if the immune system tolerates a protein. The injected mice showed a hypersensitive skin response, while the airway-exposed mice developed airway inflammation and mild lung damage.