Just as firefighters mobilize in response to a reported fire, specialized immune cells in the body mobilize in response to the introduction of foreign substances known as antigens. Plasma cells are an important type of immune cell that release antibodies (or protective proteins) that work to neutralize antigens. Recently, Japanese researchers have shed new light on the survival of plasma cells in the body.
In a recent study published in Journal of Experimental Medicineresearchers led by Osaka University have employed a new experimental system to track the development and longevity of plasma cells over time.
Plasma cells are generated by the spleen and lymphoid organs in response to exposure to antigen. Many plasma cells die shortly after participating in an immune response, but a small population of plasma cells called long-lived plasma cells (LLPCs) can survive in the body for months or even years. Researchers sought to explore the dynamics of this LLPC population to better understand how antibody-mediated immunity is maintained in the body.
Our aim was to monitor the long-term survival of plasma cells. To this end, we designed a mouse model in which plasma cells in the spleen and bone marrow were tagged by a fluorescent reporter in response to a specific drug treatment.”
Takuya Koike, lead author of the study
The researchers monitored the survival of fluorescent plasma cells in the spleen, bone marrow and intestine for over a year and found that the frequency of fluorescent plasma cells decreased to less than 60% within 1 month and by up to 3%-20%. . % within 1 year. Bone marrow appeared to contain more fluorescent plasma cells at one year than spleen or intestine, indicating that LLPCs may preferentially reside in bone marrow niches.
‘Our results indicated that the plasma cell population likely undergoes frequent turnover, with new plasma cells replenishing lost cells over time, while only a small portion of cells differentiate into LLPC,’ explains senior author Wataru Ise. Analysis of another mouse model in which only newly generated plasma cells were labeled allowed the researchers to identify specific molecular markers that can distinguish LLPCs from short-lived plasma cells.
These results provide insights into the longevity of plasma cells. A better understanding of the LLPC population may aid in the development of new vaccines that efficiently induce the generation of LLPC, thereby enhancing the body’s antibody-mediated immune response.
Koike, T. et al. (2022) Progressive differentiation to the long-lasting plasma cell compartment in the bone marrow. Journal of Experimental Medicine. doi.org/10.1084/jem.20221717.