For years, scientists studying the immune system have based their observations on snapshots of isolated cells and tissues. Now, thanks to emerging technologies, researchers can have front-row seats to the dance of immune cells occurring within living tissues.
New research, reported in three papers in the June 7 issue of the journal Science, for the first time visualizes the behavior of immune cells and their targets in intact lymph nodes. The publications open the door to important new discoveries that were not possible using previous techniques.
"It is The Immune System: The Movie," says Ronald Germain, M.D., Ph.D., deputy chief of the laboratory of immunology at the National Institute of Allergy and Infectious Diseases (NIAID) and a principal author of one of the studies. "We can now follow individual T cells within intact tissues to observe how they behave and interact with other cells as immune responses develop."
Much of our current understanding of the interplay among immune cells and their targets has been inferred from looking at chemically stained cells in thin slices of tissues observed under a microscope. Video microscopy has been used to observe the movement of cells, but its use has been limited to small samples grown in culture.
In the three new papers, researchers use two types of microscopes that can scan through a thick sample and limit their focus to living cells lying deep within the lymph nodes, the structures in the body where immune cells are activated in response to microbial invaders or other signals. According to Dr. Germain, the new technique will permit investigators to explore questions they previously could not clearly address: for example, how long do T cells remain in contact with their target cells, when do the T cells divide, and where do different types of T cells go once they have been activated.
The study by Dr. Germain and his colleagues examined how T cells interact with dendriti
Contact: Sam Perdue
NIH/National Institute of Allergy and Infectious Diseases