Navigation Links
'License to kill' enables powerful immune attack cells in mice

Scientists have discovered that a group of important immune system cells has a surprising resemblance to cinematic British superspy James Bond: the cells receive a "license" that allows them to unleash their most potent attacks on enemies.

This licensing process apparently helps reduce the chances that the cells will erroneously direct their firepower at the body's own tissues, according to researchers at Washington University School of Medicine in St. Louis. The process is very different from other previously identified ways that help immune cells distinguish invaders from self, and could have important implications for doctors struggling to understand such issues as persistent viral infections and patients' responses to bone marrow transplants. The findings will appear in the August 4 issue of Nature.

The immune cells in question already evoked cinematic connections simply by virtue of one of their names: scientists commonly refer to them as natural killer cells. The cells rapidly attack invaders and are continually generated in the bone marrow, leading to replacement of the entire population approximately once a week.

Scientists led by Wayne M. Yokoyama, M.D., the Sam J. Levin and Audrey Loew Levin Professor of Research in Arthritis, and professor of medicine and of pathology and immunology, discovered through experiments in mice that the arsenals of natural killer cells only become fully armed after a receptor on their surfaces interacts with a molecule on the surfaces of other cells.

The molecular details of the process were so unusual that Yokoyama and his colleagues found themselves struggling to develop terms to describe it to other immunologists.

"So many other terms that might have been appropriate--education, tolerance, instruction, selection--already have specialized meanings in immunology that really aren't appropriate for this unique process we've discovered," says Yokoyama, who is a Howard Hughes Medical Institut e Investigator and chief of the Division of Rheumatology at Barnes-Jewish Hospital. "Many of these terms refer to processes with a similar outcome--improved ability to distinguish between self and non-self--but this is a very different way of reaching that goal. So we came up with the term licensing."

Their results include another ironic connection to the world of cinema spies: the molecular details of the process feature a player who is comparable to a double agent. Scientists have known for some time that natural killer cells have inhibitory receptors on their surfaces.

The natural killer cells' ability to attack is inhibited when these receptors encounter a molecule known as major hiscompatibility complex (MHC) class I on the surface of other cells. MHC serves as a kind of molecular I.D. badge, helping the natural killer cells to distinguish the self from an invader.

But Yokoyama's group found that the inhibitory receptors switch roles during licensing. Although the structure of the receptors is exactly the same in immature natural killer cells, they act not as inhibitors but as enablers. In their studies, natural killer cells in mice became much more capable of mounting attacks against invaders after they first encountered the mouse version of MHC.

"The structure of these receptors on human natural killer cells is different from the mouse version, but they have a similar function," says lead author Sungjin Kim, Ph.D., research instructor in rheumatology. "We will be looking for a way to see if the human version also participates in some kind of licensing process."

The group's research was made possible by a unique mouse line created by Ted H. Hansen, Ph.D., professor of pathology and immunology and of genetics. Mice normally have many different versions of the MHC molecule, but Hansen created a line that makes only one. This was essential to the ability of Yokoyama's group to test its hypothesis.

The new findings f rom Yokoyama's laboratory could explain some puzzling outcomes in the clinic, including why some patients with hepatitis C infections can be cured while others have a chronic infection for the rest of their lives.

"This could be an important advance both conceptually and in terms of clinical practice," Yokoyama says. "It could also help us match bone marrow transplants in a way that increases the immune system's ability to fight off a relapse of the leukemia."


'"/>

Source:Washington University School of Medicine


Related biology news :

1. Modification of program enables prediction of gene transcription
2. World-first technology enables study of ancient bacteria
3. Novel protein complex enables survival in hostile environment
4. New method enables gene disruption in destructive fungal pathogen
5. New technology enables faster, more efficient cell harvest: Cell therapy meeting study
6. Prototype just-in-time medical device enables untrained bystanders to save lives
7. Protein enables discovery of quantum effect in photosynthesis
8. New drug shows promise as powerful anticancer agent
9. Mosaic mouse technique offers a powerful new tool to study diseases and genetics
10. Nanoparticles, nanoshells, nanotubes: How tiny specks may provide powerful tools against cancer
11. A more powerful and efficient engine for rice: the C3-C4 challenge
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/26/2016)... , April 27, 2016 ... the  "Global Multi-modal Biometrics Market 2016-2020"  report to ... ) , The analysts forecast the ... CAGR of 15.49% during the period 2016-2020.  ... number of sectors such as the healthcare, BFSI, ...
(Date:4/15/2016)... , April 15, 2016  A new partnership ... more accurate underwriting decisions in a fraction of ... competitively priced and high-value life insurance policies to ... With Force Diagnostics, rapid testing (A1C, ... data readings (blood pressure, weight, pulse, BMI, and ...
(Date:4/14/2016)... 14, 2016 BioCatch ™, ... today announced the appointment of Eyal Goldwerger ... Goldwerger,s leadership appointment comes at a time ... the deployment of its platform at several of the ... which discerns unique cognitive and physiological factors, is a ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... June 23, 2016 , ... In a new case report ... detail how a patient who developed lymphedema after being treated for breast cancer benefitted ... change the paradigm for dealing with this debilitating, frequent side effect of cancer treatment. ...
(Date:6/23/2016)... , June 23, 2016 ... Hematology Review, 2016;12(1):22-8 http://doi.org/10.17925/OHR.2016.12.01.22 ... , the peer-reviewed journal from touchONCOLOGY, Andrew ... escalating cost of cancer care is placing an ... result of expensive biologic therapies. With the patents ...
(Date:6/23/2016)... , ... June 23, 2016 , ... ... quality, regulatory and technical consulting, provides a free webinar on Performing ... July 13, 2016 at 12pm CT at no charge. , Incomplete investigations are ...
(Date:6/23/2016)... ReportsnReports.com adds 2016 global ... pharmaceuticals section with historic and forecast data along ... Complete report on the Cell Culture ... companies and supported with 261 tables and figures ... The Global Cell Culture Media Industry ...
Breaking Biology Technology: