Journal of Neuroscience, Vol 7, 2936-2947, Copyright © 1987 by Society for Neuroscience
Inhibition of in vitro peripheral myelin formation by monoclonal anti- galactocerebroside
B Ranscht, PM Wood and RP Bunge
This work investigates the role of galactocerebroside (GalC) in peripheral
myelin formation. A monoclonal antibody against GalC was introduced into a
myelinating culture system consisting of rat sensory neurons and Schwann
cells, without other cell types. At levels that saturated Schwann cell
surface GalC, anti-GalC IgG prevented by more than 99% the appearance of
myelin sheaths. Ensheathment and basal lamina deposition were unaffected
and many Schwann cells were in the 1:1 relationship that typically develops
between Schwann cells and axons prior to myelination. Thus, the anti-GalC
antibody did not interfere with the formation of the mesaxon but prevented
its elongation. When experimentally restrained from myelination, Schwann
cells did not accumulate the myelin proteins PO and basic protein; only low
levels were expressed. The proposed mechanism of inhibition is the removal
of GalC from Schwann cell surfaces by internalization of the GalC-anti-GalC
antigen-antibody complex. This apparently prevented the interaction of
adjacent cell surfaces during the elongation of Schwann cell membranes that
constitute the myelin lamellae.