UK scientists have discovered that our antibodies can fight viruses from inside infected cells, a major breakthrough in our understanding of how our immune system responds to viral infections, such as the common cold, gastroenteritis and winter vomiting. This latest research, from the Medical Research Council (MRC), UK, provides scientists with a new set of rules that will have a huge impact on future antiviral research.

Viruses are responsible for more human deaths than any other pathogen or disease. Twice as many people die from viruses annually than cancer. Scientists agree that viral infections are the most difficult ones to treat.

Before this discovery, the scientific community thought that antibodies could only attack viral infections outside the cells, for example, by stopping them from gaining entry into a cell.

Researchers at the MRC Laboratory of Molecular Biology, Cambridge, England, have demonstrated that even when viruses enter healthy cells, antibodies remain attached to them. As soon as they are inside a cell, a protein – TRIM21 – triggers a response which pulls the virus into a disposal system the cell uses to expel waste. The process is so fast that the virus does not usually have a chance to damage the cell.

MRC scientists found that this disposal system within cells works even faster if TRIM21 protein levels are raised. This discovery is likely to have a major impact on research into making improved antiviral medications.

Study leader, Dr Leo James said:

Doctors have plenty of antibiotics to fight bacterial infections but few antiviral drugs. 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.

Deputy director of the MRC Laboratory of Molecular Biology, Sir Greg Winter, said:

Antibodies are formidable molecular war machines; it now appears that they can continue to attack viruses within cells. 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.

The scientists explain that their current research is at basic cell level. Their findings will have to be applied to clinical trials next – something they plan to do.

Leo C. James et al.
“Antibodies Q:1 mediate intracellular ; 2 immunity through tripartite motif-containing 21 (TRIM21)”
PNAS Proceedings of the National Academy of Sciences of the USA

Written by Christian Nordqvist