Adhesion-related glycocalyx study: quantitative approach with imaging-spectrum in the energy filtering transmission electron microscope (EFTEM).
Large polysaccharide molecules composing the glycocalyx have been shown to prevent cell adhesion. However, this process was not observed microscopically. Terbium labeling, combined with a new quantitative imaging method based on electron energy loss spectroscopy, allowed specific glycocalyx staining with excellent contrast. Image analysis enabled us to compare glycocalyx structure in free membrane areas and contacts between monocytic cells and bound erythrocytes. Apparent glycocalyx thickness, in contact areas, was half of the sum of glycocalyx thicknesses in free areas without label density increase. Ultrastructural immunogold localization of CD43 molecules, a major component of glycocalyx, was also demonstrated to be excluded from contact areas during adhesion. Thus, both approaches strongly suggest that some glycocalyx elements must exit from contact to allow binding of adhesion molecules.
Soler
M
M
Unité INSERM 387 Adhesion Cellulaire, Hôpital Ste Marguerite, Marseille, France.
Desplat-Jego
S
S
Vacher
B
B
Ponsonnet
L
L
Fraterno
M
M
Bongrand
P
P
Martin
J M
JM
Foa
C
C
D015703:Antigens, CD; D002448:Cell Adhesion; D002478:Cells, Cultured / Q000648:ultrastructure; D019276:Glycocalyx / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D051917:Leukosialin; D008854:Microscopy, Electron; D012795:Sialoglycoproteins / Q000032:analysis / Q000378:metabolism; D013725:Terbium
D015703:Antigens, CD; D051917:Leukosialin; C465014:SPN protein, human; D012795:Sialoglycoproteins; D013725:Terbium