Expression of CD44 isoforms on isolated bone marrow plasma cells and peripheral CD19+ B cells of patients with multiple myeloma and healthy individuals

The expression of certain isoforms of CD44 was shown to correlate with aggressiveness and metastatic potential of various tumour types. We analysed the expression of the adhesion molecule CD44 and its variant domains (v6, v7, v7/8, v10) on isolated bone marrow (BM) plasma cells and peripheral blood (PBL) CD19+ B cells of 21 patients with MM and 15 healthy donors. B cells and plasma cells were isolated by immunomagnetic sorting and analysed by two-colour flow cytometry. The expression of CD44 isoforms was significantly higher on PBL B cells of patients with MM than in healthy controls. The elevated expression of CD44 isoforms (v6, v7/8, v10) on PBL B cells correlated with reduced overall survival in MM. CD44 isoforms were more strongly expressed on "larger", activated B cells. Furthermore, CD44 isoforms were found to be simultaneously expressed with CD38hi and CD56 on both, B lymphocytes and plasma cells of patients with MM. The determination of CD44 isoforms on circulating B cells may be helpful in defining prognostically unfavourable subgroups in MM.

Primary structure of the O-glycosidically linked glycan chain of the crystalline surface layer glycoprotein of Thermoanaerobacter thermohydrosulfuricus L111-69. Galactosyl tyrosine as a novel linkage unit

The products of Pronase digestion of the crystalline surface layer (S-layer) glycoproteins of Thermoanaerobacter thermohydrosulfuricus strains L111-69 and L110-69 were isolated by gel permeation chromatography, cation exchange chromatography, chromatofocusing, and reversed phase high performance liquid chromatography. Four compounds were obtained which were analyzed by monosaccharide analysis, one- and two-dimensional 500 and 600 MHz 1H and 13C NMR spectroscopy, methylation analysis, gas-liquid chromatography/mass spectrometry, and matrix-assisted laser desorption ionization mass spectrometry. For all glycopeptides we propose the following glycan structure with galactose as the linkage sugar. [formula: see text] The isolated glycopeptides resulted from Pronase cleavage at the glycosylated tyrosine residues. Tyrosine was found as the linkage amino acid in all fractions but the remaining amino acid sequences varied, indicating the presence of different glycosylation sites in the intact S-layer glycoprotein.

Complete structure of the tyrosine-linked saccharide moiety from the surface layer glycoprotein of Clostridium thermohydrosulfuricum S102-70

In this study, we have extended and completed a previous investigation (P. Messner, R. Christian, J. Kolbe, G. Schulz, and U. B. Sleytr, J. Bacteriol. 174:2236-2240, 1992) in which we demonstrated for the first time in prokaryotic organisms the presence of a novel O-glycosidic linkage via tyrosine. The surface layer glycoprotein of the eubacterium Clostridium thermohydrosulfuricum S102-70 is arranged in a hexagonal lattice, with center-to-center spacings of approximately 16.3 nm. Molecular weight determination by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of both glycosylated and chemically deglycosylated surface layer glycoprotein showed values for the monomeric subunits of 94,000 and 87,500, respectively. Glycopeptide fractions obtained after exhaustive pronase digestion of purified, intact glycoprotein were isolated by reversed-phase liquid chromatography. One- and two-dimensional nuclear magnetic resonance studies, together with chemical analyses and plasma desorption time-of-flight mass spectrometry, were used to elucidate the structure of the hexasaccharide moiety linked by the novel O-glycosidic linkage to tyrosine. The combined evidence suggests the following structure: beta-D-Galf-(1-->3)-alpha-D-Galp- (1-->2)-alpha-L-Rhap-(1-->3)-alpha-D-Manp-(1--3)-alpha-L- Rhap-(1-->3)-beta- D-Glcp-(1-->4)-L-Tyr.