We investigated the oligosaccharide sequence of glycoconjugates,
mainly sialoglycoconjugates, in the horse oviductal
ampulla during oestrus by means of lectin and pre-lectin
methods such as the KOH-neuraminidase procedure to
remove sialic acid residues and incubation with N-glycosidase
F to cleave N-linked glycans. Ciliated cells displayed N-linked
oligosaccharides throughout the cytoplasm. The cilia
glycocalyx expressed both N- and O-linked (mucin-type)
oligosaccharides, both showing a high variety of terminal
sequences. In the most non-ciliated cells, the whole cytoplasm
contained N-linked oligosaccharides with terminal
αGal as well as mucin-type glycans with terminal Forssman
pentasaccharides. In a few scattered non-ciliated cells, the
whole cytoplasm displayed sialylated N-linked oligosaccharides
with terminal Neu5Ac-GalNAc and O-linked glycans terminating
with neutral and/or αGalNAc, Neu5Acα2,6Gal/
GalNAc, Neu5AcGalβ1,3GalNAc. Supra-nuclear granules,
probably Golgi zones, of non-ciliated cells showed mainly O-linked
glycans rich in sialic acid residues. The luminal surface
of non-ciliated cells showed N-linked oligosaccharides,
containing terminal/internal αMan/αGlc, βGlcNAc and terminal
αGal, as well as mucin-type oligosaccharides terminating
with a large variety of either neutral saccharides or
sialylated sequences. Apical protrusions containing O-linked
oligosaccharides with terminal Forssman pentasaccharide,
Neu5Ac-Galβ1,4GlcNAc, Neu5Ac-GalNAc were seen in nonciliated
cells scattered along the epithelium. These findings
show the presence of sialoglycoconjugates in the oviductal
ampulla epithelium of the mare and the existence of different
lectin binding profiles between ciliated and non-ciliated
(secretory) cells, as well as the presence of non-ciliated cell
sub-types which might determine functional differences
along the ampullary epithelium of mare oviduct