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 wide variety of manipulations ranging from studies employing gene transfection to microinjection. There is evidence that fibroblasts in various parts of the body are intrinsically different. Fibroblasts within tissues are exposed to a dynamic mechanical environment, which influences the structure integrity of both healthy and healing soft tissue. Fibroblasts secrete a non-rigid extracellular matrix that is rich in type I and/or type III collagen. Fibroblasts are responsible for much of the synthesis of extracellular matrix in connective tissues and play a major role in wound healing. Many diseases are associated with fibroblasts, either because fibroblasts are implicated in their etiology or because of the fibrosis that accompanies damage to other cell types in tissues. HTF from ScienCell Research Laboratories are isolated from human tonsils. HTF are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HTF are characterized by their spindle morphology and immunofluorescence with antibodies specific to fibronectin. HTF are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast, and fungi. HTF 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 HTF in vitro.