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
The birth of a new protein
20.10.2017 | University of Arizona
Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research