Memory B cells are reactivated in subcapsular proliferative foci of lymph nodes, 2018, Phan et al

[Andy]

Abstract

Vaccine-induced immunity depends on the generation of memory B cells (MBC). However, where and how MBCs are reactivated to make neutralising antibodies remain unknown. Here we show that MBCs are prepositioned in a subcapsular niche in lymph nodes where, upon reactivation by antigen, they rapidly proliferate and differentiate into antibody-secreting plasma cells in the subcapsular proliferative foci (SPF). This novel structure is enriched for signals provided by T follicular helper cells and antigen-presenting subcapsular sinus macrophages. Compared with contemporaneous secondary germinal centres, SPF have distinct single-cell molecular signature, cell migration pattern and plasma cell output. Moreover, SPF are found both in human and mouse lymph nodes, suggesting that they are conserved throughout mammalian evolution. Our data thus reveal that SPF is a seat of immunological memory that may be exploited to rapidly mobilise secondary antibody responses and improve vaccine efficacy.

Open access at https://www.nature.com/articles/s41467-018-05772-7

 

[Andy]

Forgot to add this article about the study, https://www.newsweek.com/scientists-discover-new-micro-organ-hiding-our-immune-system-1086757

Scientists have discovered a new “micro-organ” within the immune system, according to a study published in the journal Nature Communications.

Researchers from Australia’s Garvan Institute of Medical Research identified a structure that “remembers” past infections and vaccinations—and is filled with immune cells of many kinds which respond to pathogens that the body has encountered before.

The structure is strategically positioned on the outside of lymph glands to detect infections early, according to researchers. It was discovered when the team used an advanced imaging technique, known as "3D microscopy", to essentially create “movies” of the immune system in action inside living animals.