Characterization of a plasma membrane protein present in non-myelin-forming PNS and CNS glia, a subpopulation of PNS neurons, perineurial cells and smooth muscle in adult rats

A plasma membrane protein common to nonmyelin-forming peripheral glia, including non-myelin-forming Schwann cells, satellite cells and enteric glia, is recognized and defined by monoclonal antibody A5E3. It is not detectable immunohistochemically on myelin-forming Schwann cells. The antigen is also present in large amounts on smooth muscle cells and perineurial cells, on some PNS neurons, and at lower levels on astrocytes of adult rat. In neonatal but not adult animals, the antigen is present on skeletal muscle fibres and myoblasts. In immunoblots and immune precipitation experiments on smooth muscle and Schwann cell extracts the antigen is a polypeptide with an apparent molecular weight of 130 kd. In being present in some non-neural tissues, albeit very highly restricted in cell type, this antigen resembles several other cell surface glycoproteins found in large amounts in the nervous system.