"Science" sub-issue cover: More pictures to show you clearly, how the brain clears viral infections

▎ Yao Ming Kant's content team editor reported a very interesting study on the cover of the June issue of science immunology, a sub Journal of science.scientists used microscope technology to see how the brain cleans out viral infections.they also found a group of cells that play a key role in it.Image Source: a. moseman et al. / science immunology in the paper, scientists pointed out that once virus infection occurs in the central nervous system, it may have very serious consequences.after all, our brain cells are difficult to self-renewal, and if one dies, one will be less.however, some phenomena we have observed are very puzzling. Br / >it provides us with a fast smell system.however, we rarely hear cases of fatal brain damage caused by nose infections.why? This is exactly what scientists want to answer in this study.they used mice as models to infect them with a dangerous virus called "vesicular stomatitis virus" (VSV).in theory, the virus can enter the brain through a nasal infection.in this way, scientists can observe the corresponding immune response.} after infection, the blue cytotoxic lymphocytes will quickly move to the green infected site (photo source: reference [1]). Of course, after the virus infection, there is a very strong immune response in the brain.the researchers observed that the antiviral activity of "cytotoxic lymphocytes" near the olfactory bulb of the infected brain slowed down significantly and began to clear the virus.} dark blue cytotoxic lymphocytes will look for signs of infection in the olfactory bulb (photo source: reference [1]). How do these lymphocytes identify the virus? Follow up studies have observed an unexpected phenomenon: it is a group of brain cells called microglia that are responsible for telling these lymphocytes what the virus looks like.although they are not infected by the virus themselves, they can obtain virus antigens from the nearby neurons and attach these antigens to themselves for lymphocyte recognition.this may play a very important role in maintaining brain function.if the lymphocytes see the infected nerve cells, they will attack them indiscriminately. Although it can solve the problem of virus infection, it will also leave irreversible damage to the cognitive ability of the brain.however, with the help of microglia, lymphocytes can eliminate viral infection in the brain in a way that does not kill cells.} when red cytotoxic lymphocytes come into contact with microglia, the calcium flux changes (green) (photo source: reference [1]) "we don't want T cells to enter the brain and kill what they shouldn't have killed," E. Ashley, one of the study's co authors Professor moseman said: "microglia acquire the antigen in a way and present it in the region, but avoid some complications, such as killing neurons."the researchers also confirmed the importance of these microglia.when microglia in the brain of mice were reduced, the ability of T cells to recognize viruses was weakened.these mice are also more likely to die after virus infection.in relevant news reports, it has been pointed out that one of the early symptoms of NCV infection is the loss of sense of smell and taste.will NCV enter the brain? How can we prevent it? We don't know yet.but this paper undoubtedly gives us a new understanding of the immune response in the brain.References: [1] E. Ashley moseman et al., (2020), T cell engagement of cross presenting microglia protection the brain from a nasal virus infection, science immunology, DOI: 10.1126/ sciimmunol.abb1817 [2] Watch: How some cells serve as unlikely heroes to defend the brain from viral invaders, Retrieved June 22, 2020, from