Organization of stromal cells in the lymph node. Lymph nodes were isolated, sectioned, and stained with fluorescent antibodies specific for lymphatic endothelial cells (red) and blood vascular endothelial cells (green). Other cells were visualized with a stain that detects their nuclei (blue). Such imaging is being used to study the movement of lymphocytes and dendritic cells into and out of the lymph node and how their localization influences the development of immune responses and immunological tolerance. Courtesy of Jarish Cohen, MSTP student in Dr. Victor Engelhard’s laboratory.