If medical researchers fail to cook up a cure for the common cold in our lifetime, it won't be for lack of trying. The cold may be a relatively trivial annoyance, but it's not even close to a trivial problem. Despite its name, for instance, the common cold is caused by not one common virus but five different viral families, encompassing a couple of hundred unique viral strains among them. These strains are sufficiently different from one another that even after catching one, we can later be infected and rendered miserable by all the others. This explains why toddlers seem to be in a continuous state of sniffles--being tabulae rasae for every strain that comes along--while adults become ever more immune with each ensuing cold and often go years before encountering a strain they've never had. The regrettable implication is that researchers will have to come up with a cure for every family and strain, or at least most of them. Otherwise any treatment is likely to fail too frequently to fire the public's enthusiasm. Curing the common cold is therefore as much a question of economics and marketing as it is of scientific genius--after all, the average cost of developing a new drug and bringing it to market is $350 million to $500 million.
To make matters worse, the cold is common only in humans. While researchers have lately managed to infect chimps with the cold virus, the animals don't seem actually to get sick. They don't even sniffle, and their mucus weight, an objective measure of symptom severity favored by cold researchers, remains unchanged. This makes it difficult to test potential cures on chimps. Rats and mice, the usual fodder for medical experiments, are blissfully unaffected. Without animal models to work with, a pharmaceutical company will very occasionally take a drug from test tube directly to human--if the condition it's potentially treating is sufficiently dire and life-threatening. To do so for an innocuous little misery like the common cold is a different story.
Nevertheless, there is an outside chance that a cure, or at least a viable treatment, is in the works. If so, the credit belongs as much to serendipity as to any single researcher. Fortunate chance played an important part in the story of a molecule known by the uninspiring name of intercellular adhesion molecule 1, or ICAM-1. As its name implies, ICAM-1 is one of a group of molecules that sit on the surface of cells and adhere to other cells when the need arises. This adhesion is critical to a wide variety of physiological processes--from making our immune systems work to keeping the cells of our bodies sufficiently stuck together that we don't all collapse on the floor in huge cellular puddles. For this reason, the discovery and understanding of intercellular adhesion molecules launched a pharmaceutical revolution that had nothing to do with the common cold and may be where the big money will lie. If any Nobel prizes are given for ICAM-1 and its kin, this will most likely be the reason.
Along the way, however, researchers noticed that ICAM-1 protrudes from cells in your nasal cavity and acts as the entryway--the doorknob, so to speak--by which most members of one particular family of common cold viruses, known as rhinoviruses, penetrates your cells, infecting them. As of last year, a specially designed version of ICAM-1 had been tested as a treatment for the rhinovirus-inspired common cold and had done remarkably well at its job. Whether ICAM-1 or some preparation derived from it will soon appear in your medicine cabinet as a cold cure may be an economic question, but the history of ICAM-1 is a quintessentially scientific tale of collaboration, competition, and luck.
