Chinese scientists have discovered that bats are lucky enough to have a gene, called Sting, which once mutated allows them to resist the worst viruses like Ebola. This gene would reduce the production of interferons, the proteins of the immune system that alert the body of a viral infection.
Bats can carry many deadly viruses, such as Nipah, Marburg, Sars or Ebola. They do not suffer any of their effects. Usually, the immune system defends the body through antibodies and a set of T cells called killer T-cells. These recognize and destroy viruses. They are able to respond with past infections or with a vaccine. Some organisms can reject a virus without ever having been infected. This is called innate immunity.
The danger of virus detection
When it infects a cell, a virus leaves traces, which will then be identified by detection proteins, in case of recurrence. These will then produce interferons. The latter will trigger the alarm effects we know, such as fever, pain and fatigue. Interferons also cause the creation of molecules with an immediate antiviral effect.
But if the body produces too much interferons, it can also be harmful. This is what happens to viruses like Ebola and Sars. The latter had infected more than 8,400 people in 2003.
“At first we thought that the bat could have a very strong innate immune system, which meant that their interferons could kill the whole virus, but we realized that these animals could live with the virus, as in a balance situation,” said Professor Peng Zhou, of the Wuhan Institute of Virology.
The role of DNA
Scientists have discovered that bats have a special distribution of their DNA. The presence of the Sting gene would make all the difference. This different composition of their body reduces the virus’s ability to produce interferons. The effects are not the same in humans.
This discovery is subject to debate by American scientists, who still doubt the responsibility of this Sting. Professor Alexander Bukreyev, based at the University of Texas Medical Department, says: “Clearly, more studies are needed to better understand the ability of bats to harbor viral pathogens.”