A previously unknown mechanism enables the immune system in the gut to respond rapidly to changes in bacteria
A RIKEN-led international research group has puzzled out details of the intricate mechanism by which the immune system in the gut can respond rapidly to changes in its bacterial environment. Eventually, the work could lead to better treatment and control of gut infections and inflammatory bowel diseases.
The gut is in direct contact with the external environment and houses at least 400 different species of bacteria in vast numbers. It maintains a finely tuned immune system built around immunoglobulin A (IgA) antibodies produced by B cells to protect the body against pathogens and manage the growth of benign organisms. Previous research by other researchers unraveled a mechanism whereby T cells control the formation of these IgA-producing B cells in organized multi-cellular structures called Peyer’s patches, which develop in the embryo. But such a system could take weeks to respond to invasive bacteria.
The latest work reveals a second mechanism that operates without intervention of T cells, and develops only after colonization of the intestine with bacteria, hence after birth. It involves another set of cellular structures called isolated lymphoid follicles (ILFs).
In a recent paper in the journal Immunity (1), the researchers, led by Sidonia Fagarasan of the RIKEN Center for Allergy and Immunology in Yokohama, detail how these ILFs piece together, providing an understanding of the newly identified mechanism. They used strains of mice bred to lack compounds significant to the development of ILFs.
The researchers noticed that the numbers and size of ILFs in the gut paralleled the level of bacteria, increasing with bacterial colonization and decreasing with the use of antibiotics. Recently, they also discovered cells in adults similar to embryonic lymphoid tissue-inducer (LTi) cells essential to the development of immune centers, such as lymph nodes and Peyer’s patches.
Fagarasan and her colleagues showed that these adult LTi cells could interact with underlying stromal cells in the gut to recruit the cellular components of ILFs—B cells and antigen-presenting dendritic cells (Fig. 1). But the adult LTi cells only did this effectively in the presence of bacterial cells which stimulate an immune response, partly through the production of tumor necrosis factor. So ILFs are only formed when bacteria are present. The researchers also demonstrated that functioning ILFs could transform typical B cells that make immunoglobulin M into those that produce IgA.
“If we can understand more about these LTi cells and their interactions,” says Fagarasan, “it could provide us with the potential to manipulate the gut immune system.”
1. Tsuji, M., Suzuki, K., Kitamura, H., Maruya, M., Kinoshita, K., Ivanov, I.I., Itoh, K., Littman, D.R. & Fagarasan, S. Requirement for lymphoid tissue-inducer cells in isolated follicle formation and T cell-independent Immunoglobulin A generation in the gut. Immunity 29, 261–271 (2008).
The corresponding author for this highlight is based at the RIKEN Laboratory for Mucosal Immunity
Complementing conventional antibiotics
24.05.2018 | Goethe-Universität Frankfurt am Main
Building a brain, cell by cell: Researchers make a mini neuron network (of two)
23.05.2018 | Institute of Industrial Science, The University of Tokyo
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
24.05.2018 | Physics and Astronomy
24.05.2018 | Power and Electrical Engineering
24.05.2018 | Materials Sciences