Journal of Neuroscience, Vol 8, 883-891, Copyright © 1988 by Society for Neuroscience
Redistribution and internalization of antibodies to galactocerebroside by oligodendroglia
CA Dyer and JA Benjamins
Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan 48201.
Glial cultures from mouse brain were used to examine the direct interaction
between oligodendroglia and antibodies to galactocerebroside (GalC). The
external surface of oligodendroglial membrane sheets showed large GalC+
patches separated by a GalC- network after exposure to anti-GalC and
fluoresceinated second antibody at 37 degrees C. However, the membrane
sheets were evenly stained when cultures were fixed prior to staining or
stained at 0 degrees C. Further, exposure to second antibody at 0 degrees C
or to Fab fragments of second antibody at 37 degrees C also gave even
staining. These results indicate that GalC is normally distributed evenly
on the surface of oligodendroglial membrane sheets, but that redistribution
or patching of GalC:anti-GalC complexes occurs by cross-linking with second
antibody at 37 degrees C. Antibodies to GalC are internalized rapidly and
specifically by oligodendroglia. This process is temperature-dependent,
and, in contrast to patching, does not require the presence of second
antibody. Internalized antibodies are seen within 1 min throughout
oligodendroglial membrane sheets, then aggregate in the sheets and in large
vein-like structures leading to the cell body. By 1 hr, the cell body is
densely packed with vesicles containing anti-GalC. By 24 hr after a 10 min
exposure to anti-GalC, internal antibody has disappeared. Anti-GalC is
recycled to the cell surface within 5 min after exposure, and continues to
appear on the surface for at least 4 hr after the pulse.