Regenerative capacity of the goldfish visual system is affected by antibodies specific to gangliosides injected intraocularly.

An association between gangliosides and neuronal regeneration in goldfish is demonstrated in the present study. A single intraocular injection of affinity purified anti-GM1 antibodies administered simultaneously with crush injury of the optic nerve, inhibits the regenerating process as expressed by two parameters: protein synthesis in the retina and in vitro sprouting ability from the retina. The retinal level of several gangliosides (such as GD3, GD1a, GD1b and GT1b) is enhanced during regeneration. Although GM1 appears to be a minor retinal ganglioside, antibodies to GM1 exert a marked effect on retinal regenerative process. It is assumed that such antibodies could interact with more abundant retinal gangliosides such as GD1b which shows enhanced biosynthesis during regeneration and which shares a similar disaccharide terminal residue with GM1.

Sprouting from chicken embryo dorsal root ganglia induced by nerve growth factor is specifically inhibited by affinity-purified antiganglioside antibodies.

The involvement of gangliosides in processes related to nerve regeneration and sprouting has been demonstrated recently. The type of interaction by which gangliosides may influence neuronal sprouting was investigated in the present work. Affinity-purified rabbit anti-GM1 antibodies were found to block the sprouting from dorsal root ganglia (DRG) of chicken embryo induced by nerve growth factor (NGF). Only a moderately inhibitory effect was produced by antibodies directed to GM2, suggesting a specific interaction between NGF and GM1. In spite of the low inhibitory effect of anti-GM2 antibodies on sprouting, their binding to dissociated DRG cells was found to be higher than that of anti-GM1 antibodies. These results emphasize the high resolution of the system and suggest that the interaction of NGF with GM1 is involved in the process of sprouting.

Antiganglioside antibodies inhibit neuritic outgrowth from regenerating goldfish retinal explants.

Antibodies elicited in rabbits against bovine brain gangliosides were applied to regenerating retinal explants to examine the role of gangliosides in the trophic effect responsible for the induction of outgrowth. The results indicate that antibodies specific to gangliosides block the neuritic outgrowth from the regenerating retinal explants. It is inferred that gangliosides function as receptors on the cell surface of the retinal explants that interact with the trophic substances inducing the outgrowth. The relevance of gangliosides to the mechanism of regeneration and development induced by trophic factors is discussed.