Science heavyweight: The immune textbook has to be changed again! Scientists have confirmed for the first time that myelin-like innate immune cells, such as macrophages, can even form antigen-specific immune memory scientific discoveries.

Today's new discovery will refresh our understanding.recently, a joint research team composed of researchers from the University of Pittsburgh and Cornell University found that congenital myeloid immune cells, such as macrophages and monocytes, can also form antigen-specific immune memory, and stimulate a stronger immune response after meeting the specific antigen next time [1]."it should be noted that macrophages and monocytes, the two innate immune cells, have never been thought to have antigen-specific immune memory. Dr. Martin H. oberbarnscheidt of the University of Pittsburgh, one of the co authors of the paper, said, "our study found that the immune memory ability of these two kinds of cells is as strong as that of adaptive immune cells such as T cells.it's amazing."according to oberbannscheidt et al., this study is expected to not only solve the problem of immune rejection that has plagued the organ transplant industry for more than 60 years, but may also give us new insights into cancer and autoimmune diseases.in a word, this finding changes our understanding of innate immune response, and immune related problems may have to be reconstructed.this important research result was published in the top journal Science. Fadi g. lakkis and Martin H. oberbarnscheidt of the University of Pittsburgh and Xian C. Li, a Chinese scientist at Cornell University, are the corresponding authors of the paper.the co first authors of the paper are three Chinese scientists: Dai Hehua, LAN Peixiang and Zhao Daqiang. In general, the human immune system consists of innate immune cells (myeloid cells such as macrophages and monocytes, and innate lymphocytes such as NK cells) and adaptive immune cells (T cells and B cells).innate immune cells are the first group of cells that recognize foreign bodies in the human body. When they find abnormalities, they will activate adaptive immune cells and stimulate a stronger immune response.and adaptive immunity has a unique skill: as long as you have a face-to-face with an intruder, they will form antigen-specific immune memory and remember the intruder.if the same intruder dares to come again next time, T cells and B cells will quickly recognize them and launch a more violent attack.at the beginning, only T cells and B cells were found to have immune memory. Now more and more studies have shown that innate lymphocytes (NK) [3] and myeloid cells [4] also have immune memory characteristics.however, it is not known whether the "memory" formed by them can stimulate a stronger specific immune response like T cells or B cells.that is to say, it is still uncertain whether the innate myeloid immune cells such as macrophages and monocytes really have specific immune memory.the research team led by lakkis and others believe that although myeloid cells are innate immune cells, they also play a very important role in host defense. Their functions should not be obscured, and the above problems must be clarified. As a research team with a strong background in organ transplantation, lakkis and his colleagues started from tissue or cell transplantation.this is mainly because immune memory is also the main cause of organ transplantation failure.generally speaking, the incidence of acute immune rejection is greatly reduced one year after the completion of transplantation, but many patients have to accept a second transplant in the rest of their life because of the subsequent chronic immune rejection. due to the existence of immune memory, the extensive use of immunosuppressive drugs can not only completely eliminate immune memory, but also bring huge health risks to patients. therefore, it is of great help to find out whether the innate immune cells have immune memory problems and how they occur. } immune cells (source: pixabay) in order to eliminate the interference of other immune cells, the researchers first constructed the model mice with T cells, B cells, NK cells and other congenital lymphocytic defects, and then transplanted allogeneic spleen cells treated with irradiation to the above-mentioned immune deficient mice. the next step is very important. After 7 days, 28 days and 49 days, the same spleen cells or other types of spleen cells were used to treat different batches of immune deficient mice. let's first look at the situation of transplantation at 7 days and 28 days. Compared with the transplantation of different types of spleen cells, mice with the same type of splenocytes showed significantly stronger immune response, which was dominated by macrophages and monocytes. to confirm this result, the same results were repeated in another model mouse with immunodeficiency. these experiments proved that macrophages and monocytes of immunodeficient mice may have acquired specific immune memory to antigens. this antigen-specific immune memory was not detected in mice after 49 days. } immune response of mice at different times and inoculated with different cells. After observing that innate immune cells do have antigen-specific immune memory, another problem perplexing researchers appears: how does this process happen? Since the specific recognition of antigens by mouse and human immune cells is dependent on MHC, researchers searched the mouse genome database for proteins expressed on the surface of myeloid cells and could bind to MHC-I. in this search, several receptor molecules have been found, one of which is called paired Ig like receptor A (pir-a), and the corresponding human receptor is lilrs [5]. after a series of studies, lakkis and his colleagues finally confirmed that pir-a regulates antigen-specific immune memory of macrophages and monocytes. whether pir-a was blocked by antibody or the gene encoding pir-a was knocked out, macrophages and monocytes of mice lost antigen-specific immune memory. } immune cells (source: pixabay) finally, the researchers verified the reliability of their findings by transplanting kidneys and hearts into mice. both knockout of pir-a gene and blocking of pir-a with antibody could significantly prolong the survival time of transplanted mice. in general, this study is the first to confirm that macrophages and monocytes, two myeloid innate immune cells, can also form antigen-specific immune memory, and they have also revealed the molecular mechanism behind them, and even found a way to inhibit such cells from forming immune memory. the researchers believe that this new discovery may end the chronic organ rejection that has plagued the organ transplant community for more than 60 years, and open a new door to the development of therapeutic drugs for tumors and autoimmune diseases. the audio course "8 lectures on small cell lung cancer" which was built by the singularity cake for 3 months, is coming online. 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