Skin sentry cells promote distinct immune responses

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 type of infection. The research, published online on July 21st by Cell Press in the journal Immunity, enhances our understanding of the early stages of the immune response and may have important implications for vaccinations and treatment of autoimmune diseases.

Dendritic cells serve as sentries of the immune system and are stationed at the body's "outposts," like the skin, where they are likely to encounter invading pathogens. When dendritic cells encounter pathogen-associated antigens (molecules that trigger an immune response), they process the antigen and present it to other responding in an effort to inititate a cellular cascade resulting in clearance of the pathogen. This is a critical part of the immune response because many responding immune cells cannot "see" antigen and initiate the proper unless the antigen is properly presented by a dendritic cell.

"There are at least three different types of dendritic cells in the skin," explains senior study author, Dr. Daniel Kaplan from the University of Minnesota. "Despite studies examining these cells, the basic question of whether skin resident dendritic cells have unique or redundant functions remains unresolved." Dr. Kaplan and colleagues developed a model of that is limited to the superficial layer of the skin and studied antigen-specific immune responses in mice lacking specific subsets of skin dendritic cells.

The researchers discovered that direct presentation of antigen by one type of dendritic cell, Langerhans cells, was necessary and sufficient for the generation of antigen-specific T helper-17 (Th17) cells but not the generation of cytotoxic lymphocytes (CTL). T play a key role in orchestrating the , whereas CTLs can directly destroy infected cells. While Th17 cells play productive roles in indirectly eliminating pathogens when their response is dysregulated, they have been implicated in autoimmune disease, Meanwhile, another subset of dendritic cells was required for the generation of antigen-specific CTLs and inhibited the ability of other dendritic cells to promote Th17 cell responses.

"Our work demonstrates that in the skin promote distinct and opposing antigen-specific responses," concludes Dr. Kaplan. "This has important implications for vaccination strategies that selectively target dendritic cell populations. In addition, the requirement for Langerhans cells in the development of Th17 cells suggests these cells may participate in the early pathogenesis of Th17 cell-mediated skin diseases such as psoriasis."

Related Stories

New origin found for a critical immune response

Mar 01, 2009

An immune system response that is critical to the first stages of fighting off viruses and harmful bacteria comes from an entirely different direction than most scientists had thought, according to a finding by researchers ...

Dendritic cells ensure immune tolerance

Mar 16, 2009

Dendritic cells are essential to the body's immune defenses. Now, Ludwig-Maximilians-Universitaet Muenchen (Germany) researchers show that they also have to protect the body from itself: They help to identify any immune cells ...

'Super' enzyme may lead way to better tumor vaccines

Dec 04, 2006

A "super" form of the enzyme Akt1 could provide the key to boosting the effect of tumor vaccines by extending the lives of dendritic cells, the immune-system master switches that promote the response of T-cells, which attack ...

Identified: Switch that turns on allergic disease in people

Jan 20, 2010

A new study in human cells has singled out a molecule that specifically directs immune cells to develop the capability to produce an allergic response. The signaling molecule, called thymic stromal lymphopoietin (TSLP), is ...

Novel method to create personalized immunotherapy treatments

Aug 05, 2008

Argos Therapeutics and Université de Montréal today announced the presentation of new information on Argos' process for developing dendritic cell-based immunotherapies for HIV. Results from the study demonstrate that loading ...

Recommended for you

How Alzheimer's peptides shut down cellular powerhouses

11 hours ago

The failing in the work of nerve cells: An international team of researchers led by Prof. Dr. Chris Meisinger from the Institute of Biochemistry and Molecular Biology of the University of Freiburg has discovered ...

User comments