The problem is in the delivery. Finding the best way to get into the correct cell and orienting the gene the right way so that it works permanently, is the challenge, says Gauldie.

"Right now we don't know how to do it easily, safely and so that it's easily reproducible. We know how to get the gene from outside to inside the cell but once inside it's not working as well as we would like it."

Gauldie's work focuses on using the common cold virus -- adenovirus -- to deliver vaccines. Since the virus easily makes its way into cells through the nose, throat or lungs, researchers have found a way to "piggyback" a gene-based vaccine onto the virus.

"It's too dangerous to work with the SARS virus to develop a vaccine," said Gauldie. "But we know the genes of the virus and have identified one of them that is the code for the protein that sticks on the outside of the SARS virus. It's called the spike protein."

That's the gene that is injected into the common cold virus. In that way, the SARS virus is crippled because it can't replicate itself. The SARS protein is delivered into the cell, which triggers the body's immune system to start fighting.

"So now we have immunity without having the true virus."

Gauldie expects to have the results of vaccine trials on mice and ferrets in a couple of weeks.

The same basic delivery principle can be adapted to a whole host of diseases including cancer, diabetes, cystic fibrosis, arthritis, HIV, hemophilia, hepatitis, respiratory problems and growth deficiencies.

It's really cutting-edge stuff. Scientists have only known enough about the human gene makeup for about 10 years. But Gauldie says it will only be 10 or 15 years before gene therapy is a commonly-used treatment.

"Things go wrong when genes don't work right or they're working too hard or there's too many or too few or they're in the wrong sequence. This is a new way of treating disease at that level."

Critics of gene-based medical research argue it's a slippery slope down from manipulating genes to fight disease to human cloning or messing around with human evolution.

"We are so far away from that, that we can't even think about how to do that," said Gauldie.

Tomorrow's Science in the City lecture is free and open to the public. It will be held in The Spectator auditorium, 44 Frid St. Doors open at 6:30 p.m. and the talk begins at 7 p.m.

To register for a seat, call 905-525-9140, ext. 24934, or send an e-mail to sciencecity@mcmaster.ca.

mmacleod@thespec.com 905-526-3408