A Schwann cell line (MSC 80) was established from purified mouse Schwann cell cultures using large doses of serum. MSC 80 cell line is an aneuploid cell line which has a doubling time of 17 hr and has been maintained through more than 110 passages. Most of MSC 80 cells are of bipolar or stellate (3-5 processes) shape. A few others are irregular in shape, gigantic, and multinucleated. All MSC 80 cells express antigens of myelin-forming Schwann cells such as S-100, 224/58, laminin, and other glycoproteins of the extracellular matrix. However, they also express the non-myelin-forming Schwann cell antigen GFAP. By time-lapse cinematography, MSC 80 cells exhibit the Schwann cell characteristic rhythmical undulations. When induced to form aggregates in agar, they form intercellular junctions and basement membrane-like structures. In addition, after transplantation in or at a distance from a lysolecithin induced lesion, MSC 80 cells form myelin around the host demyelinated axons. MSC 80 cells thus express, when isolated in vitro, some of the normal myelin-forming Schwann cell phenotype. In addition, they present the major advantage of forming myelin when associated with axons in vivo.

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Cytochemically demonstrable thiamine pyrophosphatase activity is present in the innermost Golgi element in both small and large neurons of the dorsal root ganglia in CF1, C57 black, and C57 beige mice, thus resembling the neurons of rat dorsal root ganglia. The localization of acid phosphatase (EC 3.1.3.2) activity in the large neurons of dorsal root ganglia in these mice is also similar to that in rats; it is not demonstrable in Golgi elements but is present in GERL and in three types of lysosomes apparently derived from GERL. However, the small neurons of the mouse differ from those of the rat in showing acid phosphatase activity in all elements of the Golgi apparatus. In the mouse* neurons the acid phosphatase activity of residual bodies is "latent," i.e., it is not demonstrable in well-preserved cells.The three organelles dealt with in this communication are closely related structurally, and probably functionally: (a) the Golgi apparatus, (b) GERL-a specialized region of smooth endoplasmic reticulum that is located at the "trans" (1) face of the stack of Golgi elements and that possesses cytochemically demonstrable acid hydrolase activities, and (c) lysosomes (2-4). In an early account (5), small neurons of dorsal root ganglia in 13-month CF1 mice were found to display acid phosphatase activity in the three organelles, including all "elements" (2) of the Golgi apparatus. "It remains to be established," we wrote, "if this difference from the rat findings reflects the difference in age ... or species" (5).Our present observations establish the difference to be a species difference between mouse and rat. Although acid phosphatase activity is demonstrable in the Golgi apparatus of the small neurons, the large neurons in the mouse dorsal root ganglia fail to show this activity. Another interesting difference between dorsal root neurons of mouse and rat is that in the mouse the type of lysosome known as residual body (3) does not reveal its acid phosphatase activity in well-preserved cells, i.e., this activity is "latent" as in lysosomes carefully isolated from liver homogenates (6). In contrast, two other types of lysosomes, coated vesicles and autophagic vacuoles of the type-2 variety (3), show acid phosphatase activity even when the residual bodies fail to do so. MATERIALS AND METHODSThree strains of mice were studied: CF2, purchased from Carworth Farms, Wilmington, Mass., homozygous C57 black/6J, and its beige mutant (bg/bg), both obtained from the Jackson t To whom reprint requests should.be addressed.Laboratories, Bar Harbor, Me. Animals of both sexes were used; they ranged in age from 8 to 26 weeks.As with rats, good preservation of neurons requires fixation by perfusion. Similar results were obtained by perfusion with 2.5% glutaraldehyde (Ladd Research Industries, Inc., Burlington, Vt.)-0.1 M cacodylate buffer, pH 7.4 with 0.05% CaCl2 (7) or with 2.5% glutaraldehyde-2% formaldehyde (prepared from paraformaldehyde purchased from Fisher Scientific Co.)-0.09 M cacodylate, pH 7.4, with 0.025% CaCl2 (8)...

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We have demonstrated by indirect immunofluorescence the cellular localization of a monoclonal antibody (mAb 224-58), produced after immunization of a mouse with human central nervous system (CNS) myelin. Serologically, mAb 224-58 was found to be specific for 3'-sulfomonogalactosylglycolipids, namely 3'-sulfogalactosylceramide (SGC) and 3'-sulfogalactosyl 1-O-alkyl ether 2-O-acylglycerol (seminolipid). This mAb did not bind to SGC-containing tissues such as kidney, liver, spleen, or brain, nor to muscle. However mAb 224-58 did stain positively mouse, rat, and human peripheral nerve sections. In these latter sections, mAb 224-58 was bound to Schwann cell bodies and processes. The specificity of mAb 224-58 for Schwann cells was ascertained on teased rat sciatic nerves and rat Schwann cell cultures. Cells positive for mAb 224-58 were also positive for laminin, and negative for Thy 1-1 antigens both in teased fibers and Schwann cell cultures. In addition, in teased nerve preparations, mAb 224-58-positive cells were also galactosylceramide (GalC)- and SGC-positive. Isolated Schwann cells also expressed 224-58 antigen, even after prolonged time in culture. On testis sections, which contain both SGC and seminolipid, the SGC-positive cells, i.e., the spermatogonia, were always 224-58-negative. But the other germinal cells were 224-58-positive. This suggests that although 224-58 does not discriminate between SGC and seminolipid in serological tests, these lipids in their naturally occurring membrane acquire a spatial configuration that renders them distinguishable to their respective antibody.