Science reveals new details about human immunity: protein "bomb" of killer T cells

Immune cells are the basic unit of the immune system, and also the gold standard to reflect the strength of immunity.when the human body encounters the invasion of foreign enemies, the innate immune cells will bear the brunt of it, and they will react quickly to kill the enemy.if you don't start well, cytotoxic T cells (CTLs), which are the last line of defense for human immunity, will be summoned to kill infected cells and cancer cells with a variety of biological functions.this process is well known to us.killer T cells are attacking cancer cells. Recently, in a new study published in science, research teams from Oxford University and University of Toulouse in France have revealed more details of how killer T cells attack "foreign enemies": they use protein "bombs" loaded with lethal chemicals to bomb target cells.David masopust, an immunologist at the University of Minnesota School of medicine in the United States, commented: "this study is undoubtedly an important step forward in understanding how these regular immune forces remove dangerous cells."in order to kill the larger cancer cells, two smaller killer T cells release protein" bombs ".Image Source: science has known that one of the most important weapons for killing T cells is perforin, a protein that penetrates the outer membrane of target cells.granzymes released by T cells subsequently induce apoptosis or directly kill target cells.however, it is not clear whether killer T cells only release granzyme and perforin, or whether they rely on special structures to transport the killer molecules to the target cells.to this end, Michael Dustin, an immunologist at Oxford University, and his team tracked molecules released during a lethal T cell attack.the results show that T cells load these molecules into what the team calls "supramolecular attack particles (SMAP)".by analyzing the loads in these "bombs", scientists found that SMAP contains not only perforin and granzyme, but also more than 280 other proteins.in order to observe the structure of SMAP more carefully, the researchers used random optical reconstruction microscopy, which can accurately describe individual molecules.T cells release various types of small particles encapsulated in lipids, but SMAP has a protein shell and carries granzyme and perforin at its core.Image Source: science researchers conclude that killer T cells not only release perforin and granzyme, but also transport them in a complex container.to simulate the interaction between killer T cells and their target cells, Dustin and his team placed T cells on a double layer of lipids similar to those surrounding the cell membrane. SMAP appeared on the cell membrane rapidly, which indicated that T cells began to release SMAP after adsorption. Image Source: Science some smaps remain on the surface of the membrane when researchers remove killer T cells. the team reports that smaps, like molecular mines, can kill cells in up to one day. Image Source: sciencedustin said that SMAP may have been found in studies as early as the 1980s, but until recently, researchers have not used imaging techniques to detect its structure. immunologist Christopher Mody of the University of Calgary, Canada, said: "this paper is commendable because it proposes a new paradigm to illustrate how perforin and granzyme polymerize on target cell membranes. "however, he cautions that the authors have not yet demonstrated whether killer T cells produce SMAP first and then release them, or whether they release components and then assemble SMAP at the target cells. Dustin said that the complex components of smaps suggest that they may have other functions. for example, SMAP particles contain molecules that attract immune cells and manipulate their behavior, suggesting that the transmission of information may also be one of their roles. Dustin said: "we know that SMAP is important in killing T cells, but we suspect that its effect is much more than that. Reference: supramolecular attack particles are autonomous killing entities released from cytotoxic T cells 10.1126/ science.aay9207 This official account is hosted by the Microbiological Resource and big data center of the Institute of Microbiology of the Chinese Academy of Sciences. It was written in 2019 by TOP101., which reversion of type 2 diabetes. The type 2 diabetes is a simple disease, reducing weight or reversing the condition. 2. Just now, science released ten scientific breakthroughs in 2019! 3. Science! Broccoli awakens anti-tumor gene! 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