ANI | Updated: 31 Oct 2022 01:59 IST
Melbourne [Australia], Oct 31 (ANI): The way vaccines work is by successfully generating long-lived immune cells, often for decades. These immune cells provide a defense barrier that can stop or slow reinfection, as well as a memory that allows us to identify a previous invader as a virus and eliminate it before it causes disease. Although the importance of these “long-lived plasma cells” has long been understood, how and when they are produced after vaccination has remained a mystery. The antibodies in our blood that serve as a barrier are made by these cells. A research team led by Dr Marcus Robinson and Professor David Tarlinton from Monash University’s Immune Memory Laboratory, and published in the prestigious journal Science Immunology, has shown in real time how memory cells are stored immune in the bone marrow at about one cell per hour for several weeks after immunization. The researchers used a genetic system in mice to map the gradual accumulation of these cells. This system, called time-stamping, allows researchers to indelibly mark all the plasma cells present at a given time after vaccination and go back later and identify those that have survived and are therefore long-lived. . By doing this regularly after vaccination, the researchers revealed the history of the accumulation of these long-lived cells, determining when they were produced and where they went. After receiving a vaccination, we remain immune to this disease because our bodies provide a constant supply of it. of antibodies against the immunized disease, basically making sure that we continue to have those antibodies. Although we have known the places in the body where these long-lived plasma cells are generated, including the lymph nodes, tonsils and gut, it is what makes some vaccines leaders. These cells have been known to persist for decades compared to those that disappear after a few months. Given the global interest in long-term immunity provided by COVID vaccines, there is an increased urgency to understand this process. Using a mouse model that expressed a fluorescent protein (called the TdTomato protein) only in cells that specifically produce antibodies against a specific vaccine. fluorescent cells it was possible to track individual cells as they were produced and where they were stored.
The research used a number of tools to identify only those plasma cells that were generated by the vaccine. All the plasma cells in the mouse model expressed a fluorescent protein (called the TdTomato protein), and among them, they identified those that recognized the vaccine, and finally, using the time stamp, they knew when those cells had been made. cells and therefore how old they were. According to Professor Tarlinton, studying these individual cells as they are born, mature and store themselves to protect us from repeated invasion by a particular virus or bacterium “may inform our understanding of how results in the recruitment of long-lived plasma cells.” of the study has allowed researchers to determine other aspects of building specific immunity: how these plasma cells enter the bone marrow, whether these plasma cells must displace other cells when they store in areas such as the bone marrow or if these cells “find” a niche vacated by earlier plasma cells dying or moving elsewhere Mapping these cells revealed that one particular vaccine in one mouse caused the generation of about 40,000 persistent plasma cells in the bone marrow. These cells, after the initial bloom, decline at a rate of about 0.1% per day with a half-life of about 700 days, providing both an estimate of the duration of protection and identification for study later the long-lived cells. to Professor Tarlinton, understanding how these long-lived plasma cells are generated, live and die “will inform our ability to modulate their recruitment, using different combinations of vaccines or delivery strategies, which will ultimately allow us to increase the longevity of immunity.” “In fact, there is exciting work recently published in Nature that describes how altering the mechanics of vaccination can dramatically influence the character of the immune response, and we would predict the production of these special cells that have been the focus of our work”. (ANI)