A glial cell that develops from a Schwann cell precursor. The immature Schwann cell is embedded among neurons (axons) with minimal extracellular spaces separating them from nerve cell membranes and has a basal lamina. Cells can survive without an axon present. Immature Schwann cell can be found communally ensheathing large groups of axons. [ https://www.worldcat.org/search?q=bn%3A0721662544 ]