Immuno-electron microscopy studies of normal human nerves (transverse section, London resin white staining). (A) Only endoneurial fibroblast-like cells (EFLCs) show positive staining for CD34 (electron-dense gold particles) at the level of plasma membrane (arrows); scale bar, 500 nm. (B) EFLCs are also stained by the anti-NG2 antibody (arrows); scale bar, 1 µm. (C) Only Schwann cells are stained by the anti-S100 antibody (arrows indicate gold particles at the level of the abaxonal cytoplasm of a myelinating Schwann cell: SC); a nearby EFLC is not stained (large arrow); scale bar, 1 µm. (D) An EFLC shows positive staining for nestin (cytoplasmic staining, arrows); scale bar, 500 nm.