The cells of the immune system that allow fast responses to re-infection.

Immune responses are complicated. They involve numerous types of cells and proteins, performing precise step-by-step processes. And of course, we don't know all of them yet. For example, memory B cells are a type of white blood cell that are created in lymph nodes or spleens during an infection. They stick around for years and allow rapid and strong antibody-related responses to re-infection by the same virus or bacteria. In contrast, plasma cells are much more numerous and help during an initial infection by producing antibodies, although they too can exist for long periods of time in the body.

Scientists can identify different types of B cells by markers certain proteins that they express. On the basis of specific markers, the researchers identified a subset of B cells that they determined were prone to become memory B cells, which they called pro-memory B cells. They then examined mice lacking the protein Bach2, a transcription factor required for memory B cell production. These mice are known to be deficient in producing memory B cells. The researchers found that the lack of Bach2 was associated with fewer pro-memory B cells and increased expression of genes related to a protein complex called mTORC1.

Further testing showed the importance of mTORC1. We ultimately found that mTORC1 signaling was less active in pro-memory B cells than in those that ended up being recycled. Inhibiting mTORC1 activity (in other words, inducing a state of mTORC1 hypometabolism) in the Bach2 knockout mice rescued them, allowing the mice to produce memory B cells. Additionally, in wild-type mice, artificially reducing mTORC1 activity in B cells led to the production of more memory B cells than normal, while increasing its activity had the opposite effect. However, mTORC1 activity alone could not explain everything. Experiments showed that the unique combination of Bach2 expression and reduced mTORC1 activity is necessary to become memory B cells.

Contributors are welcome to publish high quality clinical, and laboratory research as case series, reviews, guidelines, techniques and practices.

Submit manuscripts on Editorial submission & Review tracking system or attachment to email at immunogenetics@immunologyjournals.org

Contact Details
Robert Solomon
Managing Editor
Immunogenetics: open access