Scientists discover way to amp up power of killer T cells
Researchers with UCLA's Jonsson Comprehensive Cancer Center have discovered a way to amp up the power of killer T-cells, called CD8 cells, making them more functional for longer periods of time and boosting their ability to multiply and expand within the body to fight melanoma, a new study has found.
The study, done in mouse models of metastatic melanoma that had spread to the brain, has important clinical implications, as the method could boost the cancer-killing power of experimental immunotherapies being tested now in various cancers, including deadly glioblastoma and metastatic melanoma, both of which are very difficult to treat successfully.
Study senior author Dr. Robert Prins, an associate professor of neurosurgery and a Jonsson Cancer Center scientist, said the killer T cells also were better able to recognize and traffic to the cancer, which is crucial as the immune system often fails to identify malignant cells as invading enemies.
The study is published in the May issue of the peer-reviewed the Journal of Immunology.
The process Prins and his team used sought to mimic the way the T cells in the immune system recognize and fight viruses in the body, stimulating what is called the innate immune system. The innate immune system is comprised of cells that immediately defend the body from infection and frequently is not stimulated in the presence of cancer, Prins said. However, the innate immune cells can be tricked into thinking a virus is present by treating with compounds that activate Toll-like receptors (TLR).
Prins' group had previously demonstrated that TLR agonists, such as imiquimod, could synergize with dendritic cell vaccines, both in mouse models and patient clinical trials. Interleukin 12 (IL-12) is one of the predominant cytokines released when TLR are activated. In this study, they wanted to see how IL-12 would affect the CD8 T cells.
Graduate student Dominique Lisiero, first author of the study, said CD8 T cells come in a large variety of "flavors" and can be stimulated in differing ways. However, what signals and which stimuli work best to prime the cells to fight cancer was unclear. Lisiero added IL-12 to the CD8 T cells in culture, before the cells were transferred into mice with established brain tumors.
"We wanted to see if we could make these cells become better at either recognizing the tumor or killing tumor cells," she said. "We didn't know what expect, but what we found was that when we programmed these cells in the presence of IL-12, we saw that the tumors decreased in size and the mice with brain metastases survived longer. In fact, Prins said that the mice treated with killer T cells primed in the presence of IL-12 lived about 2.5 times longer than those not receiving the IL-12.
To better understand the mechanisms by which priming killer T cells in the presence of IL-12 really enhanced their function, the team focused on how these T cells responded to a different cytokine, Interleukin 2 (IL-2). IL-2, which is instrumental for the body's natural response to infection and recognition of foreign invaders, often is included in adoptive transfer immunotherapies to help the T cells survive, but it has to be given in high doses that frequently cause significant toxicity to patients. Prins and Lisiero wanted to know if adding IL-12 would enhance the sensitivity of IL-2 signaling inside the T cells.
"T cells that were primed in the presence of IL-12 had a higher expression of the IL-2 receptor, meaning the T cells had an enhanced ability to respond to the IL-2. This, we believe, allowed the killer T cells to expand and survive after being transferred into mice with brain tumors. " Lisiero said. "Because the IL-12 stimulates the IL-2 receptor, we can give much lower doses of IL-2 and still get the same anti-tumor function from the killer T cells. In patients, this may translate to reduced toxicity. Clinical trials, however, would be required to prove that this priming with IL-12 would have similar effects."
Lisiero also tested the new process on human T cells, culturing them in either IL-2 or IL-12, and studying their function in the lab. The function of the cells programmed in IL-12 was dramatically increased, Prins said, validating the work in the mouse models. Their findings are already influencing how T cells are grown in the lab, he said.
The findings also are translational to the clinic, since metastatic melanoma patients in clinical trials often are removed from the protocol when the cancer appears in their brain. Many oncologists and scientists still believe that T cells can't access the brain because of its immune privilege. This study, however, has proven in a pre-clinical model that these tumors in the brain can in fact be effectively targeted.
"The in vitro priming of mouse tumor-specific CD8 T cells in the presence of IL-12 induced a diverse and rapid anti-tumor effector activity while still promoting the generation of memory cells," the study states. "Importantly, the IL-12-primed effector T cells dramatically reduced the growth of well-established tumors and significantly increased survival to highly immune resistant, established intracranial tumors."
Provided by University of California - Los Angeles
- Interleukin-12 indicates survival prospects for melanoma patients Apr 16, 2008 | not rated yet | 0
- Interleukin-10 a prognostic factor in treatment with autologous melanoma vaccine Jun 07, 2010 | not rated yet | 0
- Scientists identify how key protein keeps chronic infection in check May 08, 2009 | not rated yet | 0
- T cell protein boosts learning May 03, 2010 | not rated yet | 0
- Th17 cells summon an immune system strike against cancer (w/ Video) Oct 29, 2009 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Pressure-volume curve: Elastic Recoil Pressure don't make sense
7 hours ago From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
23 hours ago I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
Ratio of Hydrogen of Oxygen in Dessicated Animal Protein
May 13, 2013 As an experiment, for the past few months I've been consuming at least one portion of Jell-O or unflavored Knox gelatin per day. I'm 64, in very...
Alcohol and acetaminophen
May 13, 2013 Edit: sorry for the typo in the title , can't edit I looked around on google quite a bit and it's very hard to find precise information on the...
Marie Curie's leukemia
May 13, 2013 Does anyone know what might be the cause of Marie Curie's cancer
- More from Physics Forums - Medical Sciences
More news stories
In 2008 researchers from the University of Southern Denmark showed that the drug thioridazine, which has previously been used to treat schizophrenia, is also a powerful weapon against antibiotic-resistant bacteria such as ...
Medical research 17 hours ago | 3.7 / 5 (3) | 0 |
Scientists investigating the interaction of a group of proteins in the brain responsible for protecting nerve cells from damage have identified a new target that could increase cell survival.
Medical research 23 hours ago | 5 / 5 (1) | 0
New findings by researchers carrying out experiments at the U.S. Department of Energy Office of Science's Advanced Photon Source (APS) help explain why some drugs that interact with two kinds of human serotonin ...
Medical research May 17, 2013 | not rated yet | 0 |
Peptide molecules derived from the body's natural immune system can help boost the body's defence against life-threatening blood poisoning, joint University research has uncovered.
Medical research May 17, 2013 | 4 / 5 (1) | 0 |
A new Montréal study conducted by Dr. May Faraj, associate research professor at the Université de Montréal and invited scientist at the IRCM, along with her research team and medical collaborators, shows ...
Medical research May 17, 2013 | not rated yet | 0 |
Big names in medicine are set to give an upbeat assessment of the war on AIDS on Tuesday, 30 years after French researchers identified the virus that causes the disease.
8 hours ago | 5 / 5 (1) | 0
For combat veterans suffering from post-traumatic stress disorder, 'fear circuitry' in the brain never rests
Chronic trauma can inflict lasting damage to brain regions associated with fear and anxiety. Previous imaging studies of people with post-traumatic stress disorder, or PTSD, have shown that these brain regions can over-or ...
9 hours ago | not rated yet | 0 |
(Medical Xpress)—What if the quality of your work depends more on your focus on the piano keys or canvas or laptop than your musical or painting or computing skills? If target users can be convinced, they ...
20 hours ago | 3.7 / 5 (3) | 0 |
The neural machinery underlying our olfactory sense continues to be an enigma for neuroscience. A recent review in Neuron seeks to expand traditional ideas about how neurons in the olfactory bulb might encode information about ...
19 hours ago | not rated yet | 0 |
Treatment for alcohol use disorders works best if the patient actively understands and incorporates the interventions provided in the clinic. Multiple factors can influence both the type and degree of neurocognitive abnormalities ...
18 hours ago | not rated yet | 0 |
In order to avoid harms associated with alcohol consumption, in 2009 the National Institute on Alcohol Abuse and Alcoholism issued guidelines that define low-risk drinking. These guidelines differ for men and women: no more ...
18 hours ago | not rated yet | 0 |