Immune Cell Motion Studied in Real-Ti

A technique called two-photon imaging has been employed to observe individual T cells and B cells in mice as the cells move within lymph nodes in the body. The research was reported in the May 16, 2002, issue of Science Express, the online version of Science.


The two-photon imaging system combines a pulsed laser with a light microscope. The ultra-fast laser pulses allow the imaging of cells lying relatively deep within tissues, and a computer generates three-dimensional pictures so researchers can observe the cells' activity in real-time.

"Previously, researchers had not been able to see the behavior of these cells in their native immune organs. When looking at the cells' behavior, the lymph node had been a ‘black box' with no direct information on how cells were interacting, said Dr. Ian Parker, professor of neurobiology and behavior at the University of California (Irvine, USA). "This new form of microscopy gives us an unprecedented view of how the immune system functions. The cells are moving and changing shape in ways that we've never seen; this should provide insights on how disease is combated and perhaps even how the immune system can fail.”

The researchers were able to observe that when not stimulated, T and B cells move much faster within the lymph node than had been previously reported. Furthermore, T cells were seen to abruptly change their shape, speed or direction--apparently in response to biochemical signals they receive. T cells traveled farther within the lymph nodes than B cells. In the future, the two-photon technique will be used to study cells in other areas of the immune system, such as the thymus gland, spleen, and even sites of inflammation and disease.



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University of Calif., Irvine