Could cytotoxic T cells be the key to longevity? Daily science – Up News Info

Scientists at the RIKEN Center for Integrative Medical Science (IMS) and the Keio University School of Medicine in Japan have used single-cell RNA analysis to discover that supercentenarians, that is, people over 110, have a excess of a type of cell immunity called cytotoxic CD4 T cells. Supercentenarians are something like a unique group of people. First, they are extremely rare. For example, in Japan in 2015 there were more than 61,000 people over 100 years old, but only 146 over 110 years old. And studies have found that these individuals were relatively immune to diseases such as infections and cancer throughout their lives. This led to the idea that they could have a particularly strong immune system, and the researchers set out to find out what could explain this.

To answer the question, they analyzed the circulating immune cells of a group of younger supercentenarians and controls. They acquired a total of 41,208 cells from seven supercentenarians (an average of 5,887 per subject) and 19,994 cells for controls (an average of 3,999 per subject) from five controls between 50 and 80 years old. They discovered that while the number of B cells was lower in the supercentenarians, the number of T cells was approximately the same and, in particular, the number of a subset of T cells increased in the supercentenarians. When analyzing these cells, the authors discovered that the supercentenarians had a very high level of cells that are cytotoxic, which means they can kill other cells, which sometimes represent 80 percent of all T cells, compared to just the 10 or 20 percent in controls. .

Normally, T cells with markers known as CD8 are cytotoxic, and those with the CD4 marker are not, so the authors first thought that perhaps CD8 positive cells increased. But that was not the case. Rather, it seems that the supercentennial CD4 positive cells had acquired the cytotoxic state. Interestingly, when the researchers looked at the blood of young donors, there were relatively few cytotoxic cells positive for CD4, indicating that this was not a marker of youth but a special characteristic of supercentenarians. To see how these special cells were produced, the team examined the blood cells of two supercentenarians in detail and discovered that they had emerged from a clonal expansion process, which means that many of the cells were the progeny of a single ancestral cell.

According to Kosuke Hashimoto of IMS, the first author of the article, "We were especially interested in studying this group of people, because we consider them to be a good model of healthy aging, and this is important in societies such as Japan, where aging is proceeding quickly. "

IMS Deputy Director Piero Carninci, one of the group leaders, says: "This research shows how transcription analysis of individual cells can help us understand how individuals are more or less susceptible to disease. CD4 positive cells they generally work by generating cytokines. " , while CD8 positive cells are cytotoxic, and it may be that the combination of these two characteristics allows these individuals to be especially healthy. We believe that these types of cells, which are relatively uncommon in most individuals, even young people, are useful for fighting established tumors, and could be important for immunovigilance. This is exciting, as it has given us new ideas on how people living very long lives can protect themselves from conditions like infections and cancer. "

The research, published in Proceedings of the National Academy of Sciences (PNAS), was carried out by a collaboration that includes scientists from the RIKEN Center for Integrative Medical Sciences and the Faculty of Medicine of the University of Keio.

Source of the story:

Materials provided by RIKEN. Note: The content can be edited by style and length.

Read the original here:
Could cytotoxic T cells be the key to longevity? Daily science - Up News Info