A cure for the common cold could finally be on the way, with the discovery that antibodies can fight viruses from within infected cells.
The finding changes the way scientists understand immunity to viral diseases like the common cold, 'winter vomiting' and gastroenteritis, and holds promise of a new generation of antiviral drugs.
While viruses don't get the publicity of diseases like cancer, they are actually responsible for twice as many deaths, and are mankind's biggest killer. However, they are among the hardest of all diseases to treat.
Until now, it was believed that antibodies could only reduce infection by attacking viruses outside cells or by blocking their entry into cells.
But now research from the Medical Research Council (MRC) Laboratory of Molecular Biology in Cambridge has now shown that antibodies remain attached when viruses enter healthy cells.
"Antibodies are formidable molecular war machines; it now appears that they can continue to attack viruses within cells," says the lab's deputy director, Sir Greg Winter. "This research is not only a leap in our understanding of how and where antibodies work, but more generally in our understanding of immunity and infection."
Once inside, the antibodies trigger a response, led by a protein called TRIM21, which pulls the virus into a disposal system used by the cell to get rid of unwanted material. This process happens quickly, usually before most viruses have chance to harm the cell.
The MRC scientists have further shown that increasing the amount of TRIM21 protein in cells makes this process even more effective, suggesting new ways of making better antiviral drugs.
"Doctors have plenty of antibiotics to fight bacterial infections but few antiviral drugs," says the MRC's Dr Leo James. "Although these are early days, and we don’t yet know whether all viruses are cleared by this mechanism, we are excited that our discoveries may open multiple avenues for developing new antiviral drugs."
The team hopes to move soon to clinical trials.