Ceramide, 1-O- (O-(N-acetyl-alpha-neuraminosyl)-(2-8)-O-(N-acetyl-alpha-neuraminosyl)-(2-3)-O-beta-D-galactopyranosyl-(1-4)-O-2-(acetylamino)-2-deoxy-beta-D-glucopyranosyl-(1-3)-O-beta-D-galactopyranosyl-(1-4))-.