Dendritic cells respond to something produced by the pathogen, suggests PLoS Pathogens paper.
Researchers may have identified one of the body’s earliest responses to Leishmania major. They found that injecting mice with this parasite caused immune cells in the second-shallowest layer of the skin to intercept the pathogen.
Scientists began by trying to better understand the role of dendritic cells in the dermis. They created a line of genetically modified mice whose dendritic cells produced a yellow fluorescent protein.
They then used the two-photon microscopy technique to track the movements of the cells in living mice. The researchers found that the cells were surprisingly motile around the perimeter and were actively moving around.
The team took a strain of Leishmania genetically modified to produce red fluorescent protein and injected it into the mice. The different colors allowed them to use two-photon microscopy to track both dendritic cells and parasites at the same time. They observed that the dendritic cells rapidly homed in on the injected parasites.
As a control scientists injected latex beads into the mice but the action did not cause the same response from the dendritic cells. “The dendritic cells were clearly recognizing something made by the pathogen that was provoking their response, and that’s one question we will be looking to answer in follow-up experiments,” points out coauthor Stephen Beverley, Ph.D., head of the department of molecular microbiology at Washington University School of Medicine in St. Louis.
Scientists from the University of Pennsylvania and Washington University School of Medicine in St. Louis collaborated on this research. Finding appear online in Public Library of Science Pathogens.