B cells maintain stockpiles of calcium ions (Ca2+), which are released during the course of the immune response. When the presence of a foreign antigen stimulates the B cell receptor (BCR) complex, these internal reserves of Ca2+ get released into the cell, subsequently triggering the opening of channels in the cell membrane that allow the entry of even more Ca2+.
Immunologists generally considered these ions as essential currency for many key cellular processes. “Ca2+ signaling in B cells is widely assumed to be responsible for functions including B cell development, immune response and antibody production,” says Yoshihiro Baba of the Immunology Frontier Research in Osaka University and formerly with the RIKEN Research Center for Allergy and Immunology in Yokohama. However, the direct effects of this bulk Ca2+ entry, also known as store-operated Ca2+ (SOC) influx, are poorly understood.
To examine the importance of this mechanism, Baba and colleagues genetically engineered mice whose B cells lack the genes encoding STIM1 or STIM2, two proteins involved with SOC influx1. Their results suggest that this pathway plays a far more narrowly defined role than was previously expected.
The researchers determined that these two proteins cooperatively contribute to the management of Ca2+ influx, and facilitate B cell proliferation following BCR-mediated signaling. However, they appear to have no role in the actual immune response, as mice with STIM1- and STIM2-deficient B cells were still capable of mounting an antibody response against foreign antigens.
On the other hand, both factors proved important for the function of regulatory B cells, which produce anti-inflammatory factors such as interleukin-10 (IL-10) and help prevent the immune system from over-reacting or attacking host tissues. Without these STIM proteins, mouse B cells produced only minimal amounts of IL-10. Baba and colleagues determined that the absence of STIM1 and STIM2 greatly exacerbates the incidence and severity of inflammatory pathology in a mouse model of multiple sclerosis. Since the action of IL-10 suppresses a variety of autoimmune conditions, these findings may indicate a general mechanism that could be targeted for the treatment of such disorders. “Our study suggests that a failure to balance Ca2+ levels may lead to autoimmune disease. This is a very exciting finding,” says Baba.
He and his colleagues are now keen to better understand the Ca2+-dependent anti-inflammatory B cells. “We are trying to show when and where regulatory B cells function, and what cells are targeted by them,” he says, “and to understand what type of inflammation—chronic or acute—is sensitive to IL-10-producing B cells.”
The corresponding author for this highlight is based at the Laboratory for Lymphocyte Differentiation, RIKEN Research Center for Allergy and Immunology
Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton University
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction