Breakthrough in plant seeds for drug production
produce high yields of proteins that bear a strong resemblance to
human antibodies, thus bringing the possibility of using plant
systems as an inexpensive alternative to current drug production
methods a step closer.
Working with the plant Arabidopsis, scientists at the Institute for Biotechnology (VIB) at Ghent University, managed to obtain much higher levels of antibody variants within plant seeds than has previously been possible.
Five years ago the team reported yields of over 30 per cent antibody variant in their seeds (remarkably high given the general target is nearer 1 per cent of plant protein), but this was using an antibody variant with a very simple structure and only one binding site.
In this latest study the researchers - Ann Depicker, Geert De Jaeger and Bart Van Droogenbroek - were able to produce more complex antibody variants (with two binding sites) and still maintain an impressive yield of over 10 per cent.
"Since the late 80s it has been known that plants can be used to produce antibodies, but always at a relatively low level," De Jaeger explained to In-PharmaTechnologist.com.
"Our research shows that plants can not only produce antibodies, but can do so at a cost-effective level."
According to VIB-Ghent University, working with plants to produce these proteins could make production costs 10 to 100 times lower than current production methods as it does away with the need for expensive high-tech labs and production units.
The researchers subjected the action of their antibody variant to a battery of tests in order to help establish whether the alternative production method might affect the potency of potential medicines.
Their results showed that when compared with a native antibody protecting vertebrate cells from Hepatitis A infection, the antibody variants produced in plants were just as effective in protecting cells as human antibodies.
The researchers maintain that the close similarity of the antibody variants to whole native antibodies makes them extremely useful for therapeutic and diagnostic applications, for example in the treatment of cancer. In De Jaeger's opinion, however, the first breakthrough using this technique in vivo is likely to be in a treatment for cattle.
One other major advantage of using plant seeds to produce proteins is that they act as very effective storage devices. The seeds can be stored for an extended period of time without the desired protein losing its effectiveness, which means a stock supply can always be kept on hand. Using other methods of manufacture the protein must be isolated immediately after production, giving plant seed production a clear advantage - particularly in the case of epidemics or the threat of drug shortages.
While the researchers have currently only experimented using the antibody variants against Hepatitis A, other potential targets include avian flu and hantavirus. They are currently on the look-out for other potential antibodies to work with.
