Like a burglar tripping an alarm, infectious threats within the body set off a chain reaction of signaling events that enable the immune system to mount a proper defensive response. Once the crisis is averted, populations of target-specific ‘memory’ B cells ensure that any return visit by the same pathogen will be dealt with promptly and harshly.
Memory B cells initially arise within germinal centers in spleen lymph nodes, but it has proven challenging to determine whether they continue to reside there or circulate throughout the body. By applying sophisticated cellular imaging techniques, a team led by Tomohiro Kurosaki of the RIKEN Center for Allergy and Immunology in Yokohama has now resolved this question for at least one major subset of these cells1.
B cells are primarily categorized based on the immunoglobulin protein chains they incorporate into their antibodies, and Kurosaki’s team primarily focused their attention on immunoglobulin G-expressing (IgG+) cells. Using a variety of fluorescent labeling strategies, they were able to determine that IgG+ memory cells remain clustered close to the germinal centers long after the initial immune response in mice injected with the immunostimulatory molecule nitrophenol. By comparison, immunoglobulin M-expressing (IgM+) memory cells are found scattered at discrete sites throughout the spleen.
Subsequent experiments with a fluorescent indicator of cell division showed that IgG+ cells replicate rapidly in response to a secondary challenge with nitrophenol (Fig. 1), and that this process is dependent on direct interaction with helper T cells, which are also located in close proximity to germinal centers. The communication between these two cell types appears to directly contribute to elevated production of antigen-specific antibodies. “Although preliminary, our data suggest that IgG+ memory B cells are more prone to differentiate into antibody-producing plasma cells than IgM+ memory B cells, which may contribute to regeneration of the memory pool after a secondary antigen challenge,” says Kurosaki.
The memory cell-mediated immune response is generally faster and more robust with regard to target recognition than the ‘first encounter’ with a given pathogen, and Kurosaki believes that these findings represent an important step toward understanding the efficiency of the memory cell response. “Before our study, people believed that memory B cells leave the germinal centers and are recirculated all over the body by the lymphatic system and blood,” he says. “However, our study clearly demonstrates that some IgG—but not IgM—memory B cells reside continuously near germinal centers and thus [enable] rapid activation after antigen re-challenging.”
The corresponding author for this highlight is based at the Laboratory for Lymphocyte Differentiation, RIKEN Research Center for Allergy and Immunology
1. Aiba, Y., Kometani, K., Hamadate, M., Moriyama, S., Sakaue-Sawano, A., Tomura, M., Luche, H., Fehling, H.J., Casellas, R., Kanagawa, O. et al. Preferential localization of IgG memory B cells adjacent to contracted germinal centers. Proceedings of the National Academy of Sciences USA 107, 12192–12197 (2010).
gro-pr | Research asia research news
New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg
Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Life Sciences
24.02.2017 | Life Sciences
24.02.2017 | Trade Fair News