Dendritic Cell Mystery Solved with Gene Gun Technology

Researchers have used gene gun technology to track the movement of the dendritic cells that intercept foreign proteins and transmit recognition signals to T-cells.

In draining lymph nodes, antigen-bearing dendritic cells were thought to be rare and short-lived. How such small numbers of short-lived dendritic cells could activate rare antigen-specific T-cells was unclear. To unravel this mystery, investigators at Emory University (Atlanta, GA, USA; www.emory.edu) used a gene gun to fire one-micrometer sized DNA-coated gold particles into the skin cells of transgenic mice engineered with a marker gene that could be easily detected by staining.

They reported in the August 10, 2003, online edition of Nature Immunology that the number of antigen-bearing dendritic cells that migrated to draining lymph nodes was 100-fold higher than previously estimated and that they persisted for approximately two weeks. This number of cells and their two-week life span ensured ample antigen presentation and stimulation for the rare antigen-specific T-cells in draining lymph nodes.

"This research resolves a long-standing puzzle,” explained senior author Dr. Joshy Jacob, assistant professor of microbiology and immunology at Emory University School of Medicine. "T-cells that will recognize a given foreign protein are quite rare, so it was hard to imagine how the T-cells and dendritic cells would ever meet. It is still remarkable that they do.”



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