Navigation Links
Newly discovered killer cell fights cancer

A mouse immune cell that plays dual roles as both assassin and messenger, normally the job of two separate cells, has been discovered by an international team of researchers from the United States and France. The discovery has triggered a race among scientists to find a human equivalent of the multitasking cell, which could one day be a target for therapies that seek out and destroy cancer.

"In the same way that intelligence and law enforcement agencies can face deadly threats together instead of separately, this one cell combines the ability to kill foreign pathogens and distribute information about that experience," says Drew Pardoll, M.D., Ph.D., the Seraph Professor of Oncology at the Johns Hopkins Kimmel Cancer Center.

"We think this hybrid cell speeds up immune reactions and makes the system more efficient," adds Pardoll, whose findings are reported in the February issue of Nature Medicine.

The Hopkins investigators speculate that the hybrid, dubbed "IKDC" for interferon-producing killer dendritic cell, has been missed by cancer biologists because it is rare, making up one-tenth of cells in the spleen with similar features, such as other dendritic cells, according to Frank Housseau, Ph.D., research associate at Hopkins' Kimmel Cancer Center and member of Pardoll's immunology laboratory.

Most of the immune system typically works through a web of cross-talk and signaling among a variety of cells. One of the first immune cells that invading bacteria or cancer cells - both of which carry antigens that alert the immune system - may encounter is a natural killer (NK) cell. As its name implies, NK cells deliver a deadly blow by poking holes in the invader's outer membrane. Then, NK cells secrete molecules that reach other immune cells, including dendritic cells, known as the main messenger for the immune system. Dendritic cells spread "look here" information about foreign invaders to other immune cells, but do not actually kill the invaders.

It was while investigating a particular type of dendritic cell that Housseau noticed the outer membranes of these cells were studded with what were supposed to be hallmarks of NK cells, akin to finding feathers on a dog.

"We thought we were looking at dendritic cells, but we were wrong - they were some type of NK-dendritic cell blend," says Housseau. The blended cell turned out to be a newly identified actor on the immune system stage that retains all the molecular characteristics of both NK and dendritic cells.

Probing further, Housseau scoured the surface of IKDCs to create a sketch of its molecular profile. He found that it produces both types of interferon proteins, normally secreted independently by NK and dendritic cells. He also found both NK and dendriticlike molecules on the surface of IKDCs. Housseau calculated that they account for about 10 percent of conventional dendritic cells in the spleen.

IKDCs begin their lives behaving like an NK cell. After the cell encounters a pathogen, the cell switches roles from killer to dendriticlike messenger, and, according to the researchers, the swap occurs only once. Then, the cell dies and is replenished by the bone marrow.

"When an IKDC cell switches to its messenger function, the transformation is quite astonishing," says Pardoll. The cell sprouts long, hairy tentacles called dendrites. It uses its "arms" to increase the amount of surface area it reaches to communicate and interact with other immune cells.

In the next step of their investigation, the scientists tracked the location of fluorescent-tagged IKDCs and their corresponding stage of transformation after infecting mice with bacteria called listeria. In assassin-mode, the IKDCs were found in the blood, lining of the gut, liver and other organs - all areas where there is close contact with environmental pathogens. "Here, IKDCs are ready to sense invaders and spring into action," says H ousseau.

Then, the group tracked the cells to the main messenger center of the immune system - the lymph nodes. Here, they found approximately 35 percent of the original group of IKDCs now secreting communication molecules signaling a switch to messenger-mode.

Simultaneously, Housseau's colleagues in France, led by Laurence Zitvogel at the Institut Gustave Roussy, tested whether IKDCs are culprits in killing cancer by injecting mice with a cancer drug called Gleevec, which blocks an abnormal protein produced by cancer cells, and a growth factor for NK cells. The drug-growth factor combo served as a lure, leading the IKDCs to tumors implanted in the mice. The results were that tumors shrunk in mice, which received injections of IKDCs, but not in those receiving conventional NK cells only. Evidence from the shrunken tumors revealed certain "cell-killing" proteins that could be traced to IKDCs. These results are published separately in Nature Medicine.

Housseau's group is conducting further studies to verify the role of IKDC cells in infection and cancer. Meanwhile, the group is profiling IKDC genes to find a specific marker that could help them identify a human counterpart.


'"/>

Source:Johns Hopkins Medical Institutions


Related biology news :

1. Newly-discovered class of genes determines ?and restricts ?stem cell fate
2. Newly discovered virus linked to childhood lung disorders and Kawasaki disease
3. Newly Discovered Compound Blocks Known Cancer-Causing Protein
4. Newly discovered pathway might help in design of cancer drugs
5. Newly Discovered Branding Process Helps Immune System Cells Pick Their Fights
6. Newly discovered protein an important tool for sleeping sickness research
7. Newly discovered genetic disease sheds light on bodys water balance
8. Newly Discovered Role for Heart Response Enzyme May Yield Better Heart Failure Therapy
9. Newly recognized gene mutation may reduce seeds, resurrect plants
10. Newly discovered birdlike dinosaur is oldest raptor ever found in South America
11. Fitting in: Newly evolved genes adopt a variety of strategies to remain in the gene pool
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/18/2017)... 18, 2017  Socionext Inc., a global expert in SoC-based imaging ... server, the M820, which features the company,s hybrid codec technology. A ... Tera Probe, Inc., will be showcased during the upcoming Medtec Japan ... at the Las Vegas Convention Center April ... Click here for ...
(Date:4/13/2017)... April 13, 2017 UBM,s Advanced Design and ... will feature emerging and evolving technology through its 3D ... will run alongside the expo portion of the event ... and demonstrations focused on trending topics within 3D printing ... and manufacturing event will take place June 13-15, 2017 at ...
(Date:4/11/2017)... BEACH GARDENS, Fla. , April 11, 2017 ... identity management and secure authentication solutions, today announced ... contract by Intelligence Advanced Research Projects Activity (IARPA) ... for IARPA,s Thor program. "Innovation has ... onset and IARPA,s Thor program will allow us ...
Breaking Biology News(10 mins):
(Date:10/7/2017)... ... October 06, 2017 , ... ... instruments and applications consulting for microscopy and surface analysis, Nanoscience Instruments is ... Nanoscience Analytical offers a broad range of contract analysis services for advanced ...
(Date:10/7/2017)... Oct. 6, 2017  The 2017 Nobel Prize ... scientists, Jacques Dubochet, Joachim Frank and ... cryo-electron microscopy (cryo-EM) have helped to ... structural biology community. The winners worked with systems ... routinely produce highly resolved, three-dimensional images of protein ...
(Date:10/6/2017)... ... October 06, 2017 , ... On ... and webinar on INSIGhT, the first-ever adaptive clinical trial for glioblastoma (GBM). The ... The event is free and open to the public, but registration is required. ...
(Date:10/5/2017)... ... 2017 , ... Understanding the microbiome, the millions of bacteria that live in ... Are My Future, the newest exhibit on display at the University City Science Center’s ... through the lens of the gut microbiome. , Gut Love opens October 12, ...
Breaking Biology Technology: