The most abundant cell type in lung interstitium is fibroblasts. They resemble ordinary fibroblasts but have some distinguishing features, such as long branching processes and gap junctions. HPF main function is to produce type III collagen, elastin, and proteoglycans of the extracellular matrix of the alveolar septa. Pulmonary fibroblasts (PF) play an important role in the repair and remodeling processes following injury. The controlled accumulation of fibroblasts to sites of inflammation is crucial for effective tissue repair after injury. Either inadequate or excessive accumulation of fibroblasts can result in abnormal tissue function. For example, the excess proliferation of fibroblasts contributes to the adventitial thickening observed during the development of hypoxia-induced pulmonary hypertension. HPF from ScienCell Research Laboratories are isolated from human lung tissue. HPF are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HPF are characterized by immunofluorescence with antibody specific to fibronectin. HPF are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HPF 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 HPF in vitro.