Scientists have reported that the next best thing to a cure for the common cold - a way to prevent it - may have become possible at last by using a kind of cellular illusion to trick the relentless virus.
Two teams, working separately, have deciphered the chemical hitching post that about half of all cold viruses use when they latch onto cells in the nose and infect them.This seemingly arcane discovery may be an important key to defeating one of humanity's most universal miseries.
"It is clearly feasible to develop a treatment based on what we have learned," said Dr. Timothy A. Springer of the Center for Blood Research in Boston.
Their anti-cold strategy is simple: Fool the virus.
The scientists have developed a detailed picture of the rhinovirus receptor on the cells that make up the lining of the nose. A cold occurs when a virus attaches itself to one these receptors and infiltrates the cell.
Researchers have isolated the gene responsible for making the receptor, and as a result, they can produce it in limitless quantities.
They believe they can keep people healthy by flooding their noses with copies of the receptor. If a cold virus wanders by, it will harmlessly attack a dummy receptor and never find a susceptible nose cell.
No one knows for sure whether this ploy will work, although it looks promising in a test tube. A similar scheme is being tested against AIDS.
"If it works, it would be very exciting," commented Dr. Richard Crowell, a virus researcher at Hahnemann University School of Medicine in Philadelphia.
Even if the scientific hunch is right, it will be several years before such treatment is available. There will also be drawbacks. The therapy will only work against rhinoviruses, which cause about half of all colds, but it will be powerless against other cold germs. And it probably will not stop colds once they start.
"This is not a cure. It is a scientific step," said Dr. Michael E. Kamarck of Molecular Therapeutics in West Haven, Conn.
Reports on the two teams' conclusions were published in the journal Cell. One study was conducted at the Center for Blood Research, the Dana-Farber Cancer Institute in Boston and Boehringer Ingelheim Pharmaceuticals in Ridgefield, Conn., and the other at Molecular Therapeutics, part of Miles Inc., a pharmaceutical firm.
Springer said his group has already produced a soluble form of the virus receptor, but they are attempting to develop a version that will be even more effective as a virus-fooling drug.
Experts predicted that such a treatment would probably be used as a nose spray or drops. Since it would be impractical - and probably expensive - to use the drops daily, people might take the medicine when they are especially worried about getting colds.
For instance, parents might take the treatment to protect themselves when their child brings home a cold. Or an athlete might use it to keep from catching a cold before an important game.
Scientists said the discovery resulted from combining two lines of separate research.
Springer has worked for several years on a structure on the surface of cells called intercellular adhesion molecule-1, or ICAM-1. This protein is the receptor that white blood cells use to hook themselves onto the body's tissues - one step in coordinating the response to infection and triggering inflammation.