Scientists have figured out how the herpes virus enters the human brain. The infection uses a protein to move, which the cells of our body need to reproduce and transport various substances from the external environment and back. The detailed study is published in the journal Nature.
According to WHO estimates, herpes is the most common infection in the world: up to 90% of the world's population is infected with it. This virus is of two types: the first is transmitted mainly through the mouth and causes a «cold on the lips», and the second is classified as a sexually transmitted infection.
The herpes virus of the first type has long been considered a harmless companion of mankind, which disturbs its carrier, occasionally spoiling important photos with sores in a conspicuous place. Recently, however, scientists have found that infection can be the cause of dementia and other diseases. There are no vaccines or medicines for it.
Outwardly, herpes manifests itself mainly in the form of sores on the lips, but it “lives” not in the epithelium (skin), but in the human nervous system. And for a long time it was not clear how exactly, having penetrated through the outer integument of the body, the virus enters the nerves and further to the brain.
The mechanism of the immune system also remained questionable: why the immune system does not reflect the attack on the brain. It turned out that the virus deceives and breaks a signaling protein called STING, which is responsible for the infectious safety of neurons.
To move from the skin to the brain, herpes “hijacks” the transport protein, kinesin, from epithelial cells. One of the functions of this molecule is vesicular transport: the movement of various substances from the cell to the external environment and back (for the study of this mechanism, the Nobel Prize was given in 2013).
Kinesin is a mobile protein that can also «carry loads». Herpes attaches to these molecules, even at the stage of infection in the skin. That is, it not only uses human cells for reproduction, as all viruses do, but also supplements its own device with foreign proteins. Scientists hope that in the future it will be possible to stop herpes from stealing kinesin and prevent herpes from entering the brain.