Neu5Ac(?2-3)Gal(?1-4)GlcNAc(?1-2)[Neu5Ac(?2-3)Gal(?1-4)GlcNAc(?1-4)]Man(a1-?)[Neu5Ac(?2-3)Gal(?1-4)GlcNAc(?1-2)Man(a1-?)]Man(b1-4)GlcNAc(b1-4)GlcNAc(?1-