A marker for oligodendrocytes and its relation to myelinogenesis: An immunocytochemical study with experimental allergic encephalomyelitis serum and C.N.S. cultures

Abstract

To investigate a possible marker for oligodendrocytes and its relation to myelinogenesis, experimental allergic encephalomyelitis (EAE) serum has been used to study C.N.S. cultures from the time of explantation to maturity at 26 days in vitro (DIV). Cultures of foetal mouse spinal cord were exposed for 1 h to heated (complement-inactivated), rabbit anti-bovine white matter (WM-EAE) or control serum, fixed and processed by an immunoperoxidase technique for demonstrating bound immunoglobulin (Ig) by light and electron microscopy. From 5 to 26 DIV, cells morphologically identical to oligodendrocytes displayed binding of Ig to the plasmalemma of the cell body and its processes. At 5 DIV, immunoreactive oligodendrocytes had a large nucleus and nucleolus, prominent Golgi apparatus, and microtubules but no filaments. Occasionally a centriole was present, suggesting an early stage of differentiation. In myelinated cultures (from 11-12 DIV onwards), reaction product was present on the oligodendroglial outer plasmalemma apposed to myelin and along the outer loop. Sometimes it extended into the external mesaxon, outer layer of myelin, inner mesaxon and periaxonal space. No other structures were reactive, and oligodendroglia did not bind control Ig. These findings indicate that WM-EAE serum can be used as a marker for oligodendrocytes in cultures from 5 DIV onwards. The findings that oligodendrocytes acquire the antigen(s) prior to myelination and that the antigen(s) is localized on the plasmalemma of the inner and outer loops of actively myelinating oligodendroglial processes suggest that the antigen(s) may have a role in oligodendrocyte maturation and myelinogenesis. The antigen(s) involved is not yet established, but it is probably not myelin basic protein. This marker should prove useful in studies of C.N.S. development and the demyelinating diseases.

A qualitative and quantitative ultrastructural study of glial cells in the developing visual cortex of the rat

“…Astrocytes, immature astrocytes and even very early astrocytic pre cursor cells in the ventricular zone can be marked by their content of glial fibrillary acidic protein (GFAP) (see for example Choi & Lapham 1980, Levitt 1981 or vimentin (Dahl et al 1981, Schnitzer et al 1981, Bignami et al 1982. Oligodendrocytes appear to offer a par ticularly wide range of potentially useful surface and internal markers, such as the surface antigens galactocerebroside (Raff et al 1979), an antigen or antigens that can be revealed by experimental allergic encephalomyelitis serum (Bonnaud-Toulze et al 1981), the Wolfgram proteins and carbonic anhydrase II of their cytoplasm (Roussel et al 1978, Ghandour et al 1980 and the myelin basic protein and myelin-associated glycoprotein, which these cells contain in greatest concentrations during the period of active myelin formation (Sternberger et al 1978(Sternberger et al , 1979. Despite these problems of cell identification, we believe that these findings represent a useful contribution to knowledge of glial cell development, and that they provide an essential background for future studies designed to investigate the effects on glial cell development, and/or neuron:glia ratios, of genetic mutations or of experimental manipulations such as exposure of very young animals to enriched or impoverished environments, to toxins, or to abnormal hormonal or nitritional conditions.…”

Proliferation Rate of Oligodendrocytes in Culture Can Be Influenced by Extrinsic Factors

“…Proliferation represents a main possibility for the regeneration of oligodendrocytes. The study of the regenerative capability of an oli godendrocyte population subjected to an im mune aggression is important since many re ports showed that oligodendrocytes are a target for immunologically mediated patho logical changes and that they are particularly sensitive to immune aggressions [ 1,2,8,11,12,15,16,24,25,28,29]. According to our results, the reduction of the number of oligo dendrocytes following an immune aggression enhances their proliferation rate in culture.…”