Fibroblasts are mesenchymal cells derived from the embryonic mesoderm. They have been extensively used for a wide range of cellular and molecular studies, as they are one of easiest types of cells to grow in culture. Their durability also makes them amenable to a variety of manipulations ranging from studies employing gene transfection to microinjection. In general, fibroblasts secrete a non-rigid extracellular matrix which is rich in type I and/or type III collagen. There is evidence showing that fibroblasts in various organs are intrinsically different. In the lymphoid compartment, fibroblasts construct a unique conduit system with intriguing size exclusion, which plays a fundamental role in regulating immune response and homeostasis of tissue fluids. HLF from ScienCell Research Laboratories are isolated from human lymph node. HLF are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HLF are characterized by their spindle-shaped morphology and immunofluorescence with antibody specific to fibronectin. HLF are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast, and fungi. HLF are guaranteed to further expand for 15 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Fibroblast Medium (FM, Cat. #2301) for culturing HLF in vitro.