Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Mechanism offers promising new approach for harnessing the immune system to fight cancer

St. Jude Children’s Research Hospital researchers discover how to unleash the immune system against cancer in mice without triggering autoimmune reactions

St. Jude Children’s Research Hospital scientists have discovered a way to target the immune system to shrink or eliminate tumors in mice without causing autoimmune problems. Researchers also found evidence that the same mechanism may operate in humans. The study appears in the advance online edition of Nature.

The findings provide a new target for ongoing efforts to develop immunotherapies to harness the immune system to fight cancer and other diseases.

The work focused on white blood cells called regulatory T cells. These specialized cells serve as the immune system’s police force, working to control inflammation and guard against autoimmune and inflammatory disease. Regulatory T cells can, however, interfere with the immune system’s ability to fight cancer.

In this study, investigators identified a mechanism that boosts the ability of regulatory T cells to cause problems by blocking an effective anti-tumor immune response. The same process, however, plays no role in maintaining immune balance or preventing the misguided immune attack on healthy tissue that leads to autoimmune problems, researchers reported. Blocking this mechanism led to the elimination or dramatic reduction of melanoma by the immune system in mice, without causing the autoimmune and inflammatory problems often associated with current cancer-treatment efforts that target immune regulators, scientists said.

“Regulatory T cells are a major barrier to effective anti-tumor immunity,” said the study’s corresponding author, Dario Vignali, Ph.D., vice chair of the St. Jude Department of Immunology. “We have identified a mechanism that enhances the ability of regulatory T cells to put the brakes on the immune response in tumors but plays no role in immune system maintenance. For the first time, we may now have an opportunity to selectively target the activity of regulatory T cells for treatment of cancer without inducing autoimmune or inflammatory complications.”

The mechanism is built around two proteins. One, semaphorin-4a (Sema4a), is carried on the surface of various immune cells that can spark inflammation. The other, neuropilin-1 (Nrp1), is carried on the surface of regulatory T cells.

Vignali and his colleagues used a variety of molecular and cellular techniques to show that Sema4a binding to Nrp1 turns on a biochemical pathway in mouse regulatory T cells that enhances their function, stability and survival. When scientists eliminated Nrp1 on just regulatory T cells, those cells were unable to respond to signals that normally bolstered their anti-inflammatory activity.

When investigators analyzed human regulatory T cells, they found evidence that the pathway may also serve the same role.

In addition, more than 16 months after losing Nrp1 activity in their regulatory T cells, the mice showed no signs of autoimmune or inflammatory complications. “That is significant because mice and humans that lack or have substantial defects in regulatory T cells develop lethal autoimmune disease,” Vignali said.

Knocking out or blocking the activity of Nrp1 on regulatory T cells in mouse models of several human cancers, including the deadly skin cancer melanoma, led to reduced, delayed or complete elimination of the tumors. Blocking Sema4a had a similar anti-tumor effect, researchers reported. “The impact was particularly dramatic in a mouse model of human melanoma,” Vignali said. “Mice lacking Nrp1 on regulatory T cells were almost completely resistant to developing melanoma, but did not develop any autoimmune or inflammatory complications.”

Although investigators have not yet identified which cells carry Sema4a in tumors and boost regulatory T cell function, the scientists did report that immune cells called plasmacytoid dendritic cells (pDCs) provided more than half of the Sema4a in tumors in this study. That was surprising because pDCs make up a very small percentage of immune cells, and there is a long history of suppressive interactions between regulatory T cells and pDCs in tumors, Vignali said. Both cell types are recognized as inducing the immune system to tolerate, rather than attack, tumors.

Researchers also provided new details of how the Nrp1 pathway functions, including evidence that along with bolstering the ability of regulatory T cells to suppress the immune response, the pathway also helps maintain a stable population of regulatory T cells. “This pathway does not just boost regulatory function. It may define how regulatory T cells maintain their identity,” said Greg Delgoffe, Ph.D., a postdoctoral fellow in Vignali’s laboratory. Delgoffe and Seng-Ryong Woo, Ph.D., a former postdoctoral fellow in Vignali’s laboratory, are co-first authors.

The other authors are Meghan Turnis, Cliff Guy, Abigail Overacre, Matthew Bettini, Peter Vogel, David Finkelstein and Creg Workman, all of St. Jude; David Gravano, formerly of St. Jude; and Jody Bonnevier, R&D Systems, Inc., Minneapolis.

The study was funded in part by grants (AI091977, AI039480 and AI098383) from the National Institutes of Health; a grant (CA21765) from the National Cancer Center at NIH; and ALSAC.

St. Jude Media Relations Contacts
Summer Freeman
(desk) (901) 595-3061
(cell) (901) 297-9861
Carrie Strehlau
(desk) (901) 595-2295
(cell) (901) 297-9875

Summer Freeman | Newswise
Further information:

More articles from Health and Medicine:

nachricht New potential cancer treatment using microwaves to target deep tumors
12.10.2016 | University of Texas at Arlington

nachricht Breakthrough in Mapping Nicotine Addiction Could Help Researchers Improve Treatment
04.10.2016 | UT Southwestern Medical Center

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Innovative technique for shaping light could solve bandwidth crunch

20.10.2016 | Physics and Astronomy

Finding the lightest superdeformed triaxial atomic nucleus

20.10.2016 | Physics and Astronomy

NASA's MAVEN mission observes ups and downs of water escape from Mars

20.10.2016 | Physics and Astronomy

More VideoLinks >>>