Perineurial cells are of mesenchymal origin. They make up the perineurium, which has the important role of maintaining the integrity of the internal peripheral nerve environment by creating a physical barrier that, under physiologic condition, limits the entry of biologically active proteins, infectious agents, and migration of blood-borne cells into the nerve bundles. The perineurial cells are characterized by distinct ultrastructural features, including non-branching thin cytoplasmic processes coated by an external lamina and joined at their ends by a tight junction, few organelles, actin and vimentin filaments, and numerous pinocytotic vesicles. They initially form a loose, permeable sheath around axons and Schwann cells, which may recruit them from the surrounding mesenchyme, and from which they are separated by the extracellular matrix. These cells later undergo a mesenchymal-to-epithelial transition, forming tight junctions and organizing into the perineurium. The perineurial cells are immunoreactive for vimentin and epithelial membrane antigen but not for the Schwann cell markers S100 protein.HPNC from AcceGen Research Laboratories are isolated from human spinal nerves. HPNC are cryopreserved at passage one and delivered frozen. Each vial contains ＆gt;5×10^5 cells in 1 ml volume. HPNC are characterized by immunofluorescent method with antibodies to Vimentin, S100, GFAP and CD90. HPNC are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HPNC are guaranteed to further expand for 15 population doublings in the conditions provided by AcceGen Research Laboratories.
