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 to effective tissue repair after injury. Either inadequate or excessive accumulation of fibroblasts could 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-a from ScienCell Research Laboratories are isolated from adult human lung tissue. HPF-a are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HPF-a are characterized by immunofluorescence with antibody specific to fibronectin. HPF-a are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HPF-a 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 the culturing of HPF-a in vitro.