Immune response to isolated oligodendrocytes

In vitro studies of glial cells: what can we learn about demyelinating diseases?

Acquired demyelinating diseases of the central and peripheral nervous systems comprise an important group of neurologic diseases of unknown etiology and incompletely understood pathogenesis. Cultures of glial cells are proving highly useful in investigating the role of both antibodies and cytokines in the pathogenesis of these disorders. While there clearly is need for comparative studies employing more complex systems and using patient derived tissues, glial cell cultures provide important advantages by allowing researchers to characterize the effect of cytokines and growth factors on specific cell types in controlled conditions.

Lymphocyte proliferative response to glial cells in SJL/J mice immunized with rat whole spinal cord and rat myelin basic protein

Lymph node cells (LNC) from SJL/J mice immunized with either rat whole spinal cord (WSC) homogenate or rat myelin basic protein (MBP) in the presence of complete Freund's adjuvant were assayed for their in vitro proliferative response to MBP and whole or sonicated purified oligodendrocytes (OD), and astrocytes. WSC-immunized mice displayed a strong and persistent response to both syngeneic and rat OD, that disappeared after sonication (suggesting a preferential recognition of surface OD antigen(s], and a much weaker response to rat MBP. LNC from MBP-immunized mice showed a small response to MBP, but no response to OD, indicating that OD are not able to present their endogenous MBP to lymphocytes. Conversely, rat astrocytes (whole or sonicated), isolated from cultures initially comprising OD, could trigger the proliferative response of MBP-sensitized LNC, suggesting that astrocytes may act as antigen-presenting cells for OD products.

Radioimmunoassay for detection of anti-oligodendrocyte antibodies

A solid phase radioimmunoassay (RIA) for detection and quantitation of rabbit anti-oligodendrocyte antibody has been developed using bovine oligodendroglia preparation. The assay is simple, rapid, reproducible and economical. It is approximately 150 x as sensitive as immunofluorescence. Specificity has been established by using different bovine tissue antigens as substrate and absorption studies. This assay represents a potentially powerful tool for the detection and quantitation of anti-oligodendroglial antibodies and oligodendroglial antigens in serum and CSF of man and experimental animals.

Expression of antigenic markers during the development of oligodendrocytes in mouse brain cell cultures

The expression of myelin basic protein (MBP) and galactocerebroside (GC), two antigenic markers for oligodendrocytes, was checked on 7-, 14-, 21- and 28-day-old dissociated mouse brain cell cultures (BCC) by using the indirect immunofluorescence method with double staining. The number of GC positive cells increased between the 7th and the 14th day of culture before a steady state was reached. In contrast to this, the MBP-positive cells appeared only on the 14th day of culture, and their number increased with the age of the culture. In double staining, the serum produced against isolated oligodendrocytes shows the same picture as the anti-GC serum, while only a part of GC-positive cells showed also the presence of MBP. Our data suggest that the GC appears very early on the membrane of the oligodendrocytes during development while cells exhibiting both GC and MBP probably represent a more differentiated oligodendrocyte population.

Multiple sclerosis serum and cerebrospinal fluid immunoglobulin binding to Fc receptors of oligodendrocytes

Suspensions of bovine oligodendrocytes were used to study the immunofluorescent staining properties of sera from multiple sclerosis (MS) patients and normal individuals. All sera (14 MS patients, 8 patients with other neurological diseases, and 11 normal individuals) showed positive oligodendrocyte staining by indirect immunofluorescence. Staining persisted after extensive absorption of sera with bovine liver to remove nonspecific binding. Similar findings were obtained for cerebrospinal fluid from all 5 MS patients as well as all 5 patients with other neurological diseases. In additional studies to determine if binding is mediated by the Fc fragment of IgG, results were: (1) ultracentrifuged normal and MS sera failed to react with oligodendrocytes, (2) positive staining with oligodendrocytes was observed after heat aggregation of IgG, (3) ox red blood cells, complexed with antibody, reacted with oligodendrocytes to produce strong rosette formation, and (4) the rosette formation could be blocked by prior treatment of oligodendrocytes with heat-aggregated IgG. The studies fail to support a previous claim for specific binding of immunoglobulins to oligodendrocytes in MS. However, they confirm and extend previous findings that the binding of IgG to oligodendrocytes may not necessarily be an antigen-antibody reaction. Therefore, adherence reactions with a putative antibody must exclude Fc-mediated binding.

Immunological properties of bulk isolated mouse oligodendrocytes

Mouse oligodendrocytes were isolated in bulk. These cells were 95% galactocerebroside-positive. Rabbit anti-mouse oligodendrocyte antisera reacted in radioimmunoassay and in indirect immunofluorescence with mouse oligodendrocytes in suspension or in culture. The activity of the sera was not blocked by adsorption with galactocerebroside or by preincubation of cells with anti-galactocerebroside serum, although it cross-reacted with galactocerebroside in a serological test. The staining was not impaired by the pretreatment of cells with trypsin, neuraminidase or acetone, nor by adsorption of serum with myelin basis protein.

Antisera to bovine oligodendroglia raised in guinea pigs bind to surface of rat oligodendroglia and Schwann cells

Antisera against bulk isolated bovine oligodendrocytes was raised in 2 guinea pigs (GPaBO). The sera bound only to surface of rat oligodendrocytes in dissociated rat corpus callosum and cerebellar cultures and only to surface of Schwann cells in primary and secondary sciatic nerve and dorsal root ganglia cultures as determined by indirect immunofluorescence. No cells in muscle or retinal cultures bound the guinea pig antisera. The shared antigen does not seem to be either galactocerebroside (GalC) or a myelin basic protein. GPaBO can serve as a useful marker in double-label experiments to identify oligodendrocytes and Schwann cells in dissociated cultures.