The research confirmed, at the genomic level, that the immune system response to the virus, and not the virus by itself, results in common cold symptoms. Data generated by the study will be crucial in the search for new treatments for the common cold, the company said.
Specifically, the study identifies several categories of therapeutic targets that could balance the immune response in order to minimize symptoms during an infection and potentially even lead to therapies that may prevent infection.
In the randomized, placebo-controlled study, researchers infected 17 volunteers with rhinovirus-16 and an additional 18 volunteers were given a sham inoculation in the form of a nasal saline spray. The rhinovirus-16 used in the study was first isolated and purified by Procter & Gamble and the University of Virginia.
Approximately 48 hours after inoculation, the expression of 6,530 genes in infected volunteers were significantly either up-regulated or down-regulated compared to the same genes in the control group. In other words, rhinovirus infection triggered a massive immune response in the nasal mucosa. Because rhinovirus is not as destructive as other more serious viral infections, this response appears to be disproportionate to the threat, the company said.
The researchers classified the active genes according to function, and found many involved in a process known as chemotaxis, which recruits various immune cells to the site of infection. These particular genes have been correlated with symptoms such as inflammation, congestion and runny nose. Other groups of active genes have also been classified; among them are genes which make antiviral compounds thought to help thwart infections.
Lynn Jump, principal researcher at Procter & Gamble (P&G) and study author, said: “This study shows that after rhinovirus infection, cold symptoms develop because parts of our immune system are in overdrive. The findings are important because they provide us a blueprint for developing the ideal cold treatment: one that maintains the body’s natural antiviral response while normalizing the inflammatory response.”