Experts discover new activation mechanism for these immune cells

Mar 26, 2012 08:03 GMT  ·  By
This is a microscopic image of a dendritic cell in a tuberculoid leprosy lesion, showing co-expression of the intracellular receptor NOD2 (red) and cell surface IL-32 (green)
   This is a microscopic image of a dendritic cell in a tuberculoid leprosy lesion, showing co-expression of the intracellular receptor NOD2 (red) and cell surface IL-32 (green)

A group of investigators from the University of California in Los Angeles (UCLA) announces the discovery of a new mechanism that may lead to the activation of immune system cells called T cells.

Unlike other activation mechanisms, the new one is extremely potent, and brings to life a group of white cells that are very good at fighting off infections. The team used Mycobacterium leprae, the bacteria that causes leprosy, as a test subject.

The research was primarily conducted on dendritic cells, specialized immune cells that usually migrate to infection sites, and play an important role in relaying information about the pathogens to other immune cells. In time, they can become even more specialized, depending on what they're faced with.

Information they send out is very important for activating T cells, and calling on them to join the fight against invading microorganisms. Details of these interactions appear in the March 25 online issue of the journal Nature Medicine.

With the new study, experts managed to gain a clearer understanding of how dendritic cells become more specialized in addressing specific types of infections. A protein called NOD2 was found to play an important role in this regard.

This cell-signaling molecule, also known as interleukin-32, forces standard immune cells called monocytes to morph into dendritic cells, and carry relevant information throughout the bloodstream.

“This is the first time that this potent infection-fighting pathway with dendritic cells has been identified and demonstrated to be important in fighting human disease,” researcher Mirjam Schenk explains.

The expert, who was the first author of the new study, holds an appointment as a postdoctoral scholar in the UCLA David Geffen School of Medicine's Division of Dermatology. In the research, experts incubated cells containing M. leprae, and watched this protein at work.

“We were surprised to find the high potency of the dendritic cells in triggering certain specific T cell responses, which may be useful in developing new therapeutic strategies for infectious diseases and cancer,” adds Dr. Robert Modlin.

He is a senior investigator at the Geffen School of Medicine, the chief of dermatology at the institute, and also the UCLA Klein Professor of Dermatology.

He concludes by saying that the study was made possible by grants from the US National Institutes of Health (NIH), the National Institute of Allergy and Infectious Diseases and National Institute of Arthritis and Musculoskeletal and Skin Diseases.