IN-VITRO MODULATION OF CHANGES IN GANGLIOSIDE PATTERNS OF DIFFERENTIATING NEURONS IN THE PRESENCE OF AN ANTI-GM1 ANTIBODY

Retinal cells from 7-day-old chicken embryos were cultured in the pres ence of a polyclonal anti-GM1 antibody, at low and high density in a ' 'sandwich cell culture''. Cells that were about 80% neurofilament posi tive at all times, changed their morphology and emitted processes as c ontrols. By examining immunocytochemical expression of gangliosides, c ells cultured in the presence of the antibody maintained GD3 expressio n longer than controls, albeit the expression of the gangliotetraosylg angliosides (GTOG) was not considerably affected. This leads to an ext ension of the transient period in which differentiating cells coexpres sed both types of gangliosides (GD3 and GTOG). At 3-4 days in vitro th e relative synthesis of GD3 was about 30% higher and that of GD1a abou t 40% lower than in controls, indicating a delay in the shift of the s ynthesis pattern. Nevertheless, the pattern of ganglioside composition resembled at 4 days in vitro.