The receptor called Dectin-1, studied in the laboratory of David Underhill, PhD, an associate professor in Cedars-Sinai’s Inflammatory Bowel and Immunobiology Research Institute, detects fungi and instructs white blood cells whether to expend the energy needed to devour the invading pathogens. The findings are featured as the cover story in the April 28 edition of Nature.
Although scientists long have theorized how immune cells recognize microbial debris sloughed from invading organisms at some distance from themselves, this study establishes a model to explain how immune cells determine when pathogens are directly in contact with their surface and thus pose a significantly greater risk, demanding rapid destruction.
The study is important because it moves scientists one step closer to understanding the mysteries of how our bodies mount an immune response to fight disease.
In early stages of infection, white blood cells patrol the body looking for invading pathogens. Dectin-1, a receptor on the surface of white blood cells, recognizes specific components of fungal cell walls, and alerts or “switches on” the immune cells to prepare to fight the infection.
“Our lab has been studying Dectin-1, which directs white blood cells to eat and kill the fungi that they encounter directly, but to ignore soluble material sloughed off of the fungal surface which does not pose an immediate threat,” said Helen Goodridge, PhD, first author on the study and a researcher in the laboratory headed by Underhill. “This is important because phagocytosis and anti-microbial defense responses are energy-intensive and destructive, and should only be used when absolutely necessary.”
During phagocytosis, a white blood cell encounters a microbe, engulfs it, and eats it. Once inside the cell, the microbe can be killed using a combination of degradative enzymes, highly reactive chemicals, and an acidic environment.
A molecular structure that the Underhill lab calls a “phagocytic synapse” forms at the surface of the white blood cell when Dectin-1 detects fungi. As a phagocytic synapse forms, two inhibitory proteins that block transmission of signals inside the white blood cell are pushed aside. This allows Dectin-1 to instruct the cell to respond. The phagocytic synapse does not form when Dectin-1 encounters soluble fungal debris, so the white blood cell does not respond.
“The phagocytic synapse resembles another molecular structure, the ‘immunological synapse.’ It is critical at later stages of an immune response,” said Underhill. “It appears that the phagocytic synapse may be an evolutionary precursor of the immunological synapse.”
The study was funded by the National Institutes of Health, the American Heart Association, and the Crohn’s and Colitis Foundation of America. Underhill, who also directs the PhD Program in Biomedical Sciences and Translational Medicine at Cedars-Sinai, is the Medical Center’s Janis and William Wetsman Family Chair in Inflammatory Bowel Disease Research.
Nationally known for its high quality patient care, the Cedars-Sinai Health System includes a major research enterprise and ranks among the top 10 independent medical centers in terms of NIH research funding. With more than 850 research projects under way, Cedars-Sinai focuses on translational studies that move advances directly from the laboratory to the bedside.
Nicole White | Cedars-Sinai Medical Center
Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care
Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses