Cancer 'turns off' important immune cells, complicating experimental vaccine therapies

August 30, 2012

A research report published in the September 2012 issue of the Journal of Leukocyte Biology offers a possible explanation of why some cancer vaccines are not as effective as hoped, while at the same time identifies a new therapeutic strategy for treating autoimmune problems. In the report, scientists suggest that cancer, even in the very early stages, produces a negative immune response from dendritic cells, which prevent lymphocytes from working against the disease. Although problematic for cancer treatment, these flawed dendritic cells could be valuable therapeutic tools for preventing the immune system from attacking what it should not, as is the case with autoimmune disorders and organ transplants.

"Immunotherapy of cancer has been an elusive research target that, though promising, never seems to 'get there,'" said José Alexandre M. Barbuto, Ph.D., from the Laboratory of Tumor Immunology, Department of Immunology, Institute of Biomedical Sciences at the University of São Paulo, in São Paulo, Brazil. "This study helps us to better understand the mechanisms by which tumors avoid immune recognition and rejection and may, therefore, teach us how to actually engage effectively the immune system in the fight against tumors, thus achieving much better clinical responses and, consequently, quality of life, in our therapeutic approaches."

To make this discovery, researchers obtained a small sample of blood from , and from healthy volunteers. The blood cells were then separated and induced to become dendritic cells. Researchers then used these laboratory-generated dendritic cells to induce responses from other , namely lymphocytes. While dendritic cells from the healthy donors induced vigorous lymphocytic responses, from cancer patients induced mainly the activation of a specific type of lymphocyte, a regulatory lymphocyte that works as a "brake" for other types of lymphocytes.

"Understanding why the immune system does not recognize and eliminate cancer is critical to developing effective immunotherapies to fight the disease," said John Wherry, Ph.D., Deputy Editor of the . "Immunologists have been trying to unravel the answer to this question for decades and have realized that the problem is both on the immune system side, and because cancer cells appear to actively 'fly under the radar' avoiding immune system detection. This article offers insights into the underlying mechanisms regulating a key immune cell type, the dendritic cell, involved in initiating anti-tumor responses."

Explore further: Skin sentry cells promote distinct immune responses

More information: Rodrigo Nalio Ramos, Lilian Sally Chin, Ana Paula S. A. dos Santos, Patrícia Cruz Bergami-Santos, Fábio Laginha, and José Alexandre M. Barbuto. Monocyte-derived dendritic cells from breast cancer patients are biased to induce CD4+CD25+Foxp3+ regulatory T cells. J Leukoc Biol September 2012 92:673-682; doi:10.1189/jlb.0112048

Related Stories

Skin sentry cells promote distinct immune responses

July 21, 2011
A new study reveals that just as different soldiers in the field have different jobs, subsets of a type of immune cell that polices the barriers of the body can promote unique and opposite immune responses against the same ...

Discovery of immune cells that protect against multiple sclerosis offers hope for new treatment

August 16, 2012
In multiple sclerosis, the immune system attacks nerves in the brain and spinal cord, causing movement problems, muscle weakness and loss of vision. Immune cells called dendritic cells, which were previously thought to contribute ...

Recommended for you

Whole food diet may help prevent colon cancer, other chronic conditions

September 21, 2017
A diet that includes plenty of colorful vegetables and fruits may contain compounds that can stop colon cancer and inflammatory bowel diseases in pigs, according to an international team of researchers. Understanding how ...

New kinase detection method helps identify targets for developing cancer drugs

September 21, 2017
Purdue University researchers have developed a high-throughput method for matching kinases to the proteins they phosphorylate, speeding the ability to identify multiple potential cancer drug targets.

Poliovirus therapy induces immune responses against cancer

September 20, 2017
An investigational therapy using modified poliovirus to attack cancer tumors appears to unleash the body's own capacity to fight malignancies by activating an inflammation process that counter's the ability of cancer cells ...

Scientists restore tumor-fighting structure to mutated breast cancer proteins

September 20, 2017
Scientists at the Virginia Tech Carilion Research Institute have successfully determined the full architecture of the breast cancer susceptibility protein (BRCA1) for the first time. This three-dimensional information provides ...

Brain cancer growth halted by absence of protein, study finds

September 20, 2017
The growth of certain aggressive brain tumors can be halted by cutting off their access to a signaling molecule produced by the brain's nerve cells, according to a new study by researchers at the Stanford University School ...

New clinical trial explores combining immunotherapy and radiation for sarcoma patients

September 20, 2017
University of Maryland School of Medicine researchers are investigating a new approach to treat high-risk soft-tissue sarcomas by combining two immunotherapy drugs with radiation therapy to stimulate the immune system to ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.