Viruses might be plotting together to invade humans! A new study published in Nature shows that the organisms communicate with one another via messages to decide as to the next step of infection in their hosts.
If viruses were not already scary, a new research has shown a spookier side of theirs: they can leave messages for their relatives and for individuals of subsequent generations. The purpose of this communication is to assist one another in the process of infection. Yes, viruses happen to be organised invaders which apparently consult with each other regarding their evil plans!
The study, conducted by researchers from the Weizmann Institute of Science, also stands out because it is claimed to be the first one to demonstrate that viruses communicate among themselves. The “short posts” that the organisms write are meant to help others of their kind to decide the next step following infection. Viruses will often have to choose between immediately replicating inside their hosts (thus killing the latter’s cells fast) and becoming dormant. The latter strategy is what deadly HIV, and herpes do—they decide to lie in wait. So, how do they help one another to choose dormancy over a quick invasion? The team, led by research student Zohar Erez, discovered that bacteria-targeting phages would secrete small molecules during infection which could later be spotted and read by other phages.
Upon stumbling on this secret message, the tiny molecules, Sorek and his colleagues grew bacteria, and infected them with phages. After the latter left the said molecules, the bacteria and the phages were removed from the medium. More bacteria were then grown in the same medium where the small molecules were left, and they were eventually infected with the same strain of phages. The team observed that the new phages had opted for dormancy instead of murder—a decision made in the presence of high concentrations of the molecule.
Further scrutiny exposed the communication molecule to be a peptide (whose gene was later identified) and was named arbitrium, Latin for decision.
“At the beginning of infection, it makes sense for the viruses to go the fast-replication, kill-the-host route,” explains one of the authors, Prof. Sorek, “but if they are too gung-ho, there won’t be any hosts left for future generations of viruses to infect. At some point, the viruses need to switch strategies and become dormant. The molecule we discovered enables each generation of viruses to communicate with successive generations by adding to concentrations of the arbitrium molecule. Each virus can then ‘count’ how many previous viruses have succeeded in infecting host cells and thus decide which strategy is best at any point in time.”
As the team marched forward in their investigation, they found that many other related phages had similar molecules, but each bearing a small variation.
“We deciphered a phage-specific communication code. It is as if each phage species broadcasts on a specific molecular ‘frequency’ that can be ‘read’ by phages of its own kind, but not by other phages,” says Prof. Sorek.
Now, how is this useful information to us? The authors explain that viruses infecting humans might be leaving behind messages in the same way as bacteria-infecting phages do.
“We don’t really know how viruses that infect the human body decide to go dormant. It is possible that a similar strategy to that of the phages could be used by viruses that infect us.”
If this is so, intercepting these messages (if they exist) might help us tackle the viral infections before the viruses invade humans!