Glycoprotein analysis of middle ear effusions by rectin-conjugated sepharose affinity chromatography

We analyzed the composition of glycoproteins in serous and mucoid middle ear effusions (MEE) collected from patients with chronic otitis media with effusion (OME), and compared this with plasma glycoproteins, using rectin-conjugated sepharose. The concentration ratio of rectin-absorbed glycoproteins to total protein concentration in serous MEE resembled that in plasma, although mucoid MEE had a higher concentration ratio than that of the serous effusions. By SDS-polyacrylamide gel electrophoresis analysis, the molecular weight pattern of glycoproteins adsorbed to wheat germ agglutinin (WGA) gel in serous MEE was more similar to that in plasma than in the mucoid effusions. Using 2-mercaptoethanol, the basic low-molecular-weight components of the glycoproteins were almost identical in MEE and in plasma. Our findings show that mucoid MEE has a greater amount of plasma and epithelial glycoproteins than does serous fluid. The composition of these latter substances is more similar to that of plasma glycoproteins. The strong disulfide bonds present in glycoproteins may significantly contribute to the physicochemical properties of mucoid MEE.