Developmental regulation of presence of binding sites for neoglycoproteins and endogenous lectins in various embryonic stages of human lung, liver and heart

Abstract

Protein-carbohydrate interactions are supposed to play key roles in the mechanisms of cell adhesion, biosignalling and intracellular routing, warranting the analysis of the developmental course of expression of epitopes of this system. Thus, a panel of carrier-immobilized carbohydrate ligands was used as probes, namely lactose,N-acetylgalactosamine,N-acetylglucosamine, mannose, fucose and maltose. Additionally, an antibody to an endogenous β-galactoside-binding lectin (anti-galectin-1), the biotinylated lectin and two further human lectins, namely the macrophage migration inhibitory factor-binding sarcolectin and serum amyloid P component (SAP) that displays selectivity for sulphated sugars and mannose-6-phosphate, were included. They enabled us to assess the extent of the presence of respective binding sites in fixed sections from human lungs (pulmonary epithelial cells), livers (hepatocytes) and hearts (myocard cells) of 10-50 weeks gestation. Invariably, specific binding was detected in the three organ types, at least in certain stages. In most of the cases, the intensity of staining exhibited developmental regulation. The apparent patterns reveal similarities between the different cell types, as seen with immobilizedN-acetylglucosamine as well as with labelled galectin-1 and sarcolectin. However, drastic differences among such patterns with nearly opposite developmental courses do also occur, as detected for carrier-attached mannose and maltose residues. These results point to a potential importance for the detected glycohistochemical features in human development and substantiate the possibility of differential regulation of the presence of binding sites for distinct sugars within a certain organ and between the individual cell types of the monitored organs.

Pulmonary metastases of breast carcinomas: Ligandohistochemical, nuclear, and structural analysis of primary and metastatic tumors with emphasis on period of occurrence of metastases and survival

“…Their synthetic preparation or purification, labeling under activity-preserving conditions, and the set of positive and negative controls were performed, as described in detail elsewhere [18,19,[27][28][29]35,36]. The ligandohistochemical procedures were based upon the avidin-biotin complex (ABC) technique, using a concentration of 10 g/ml and an incubation time of 60 min, as described previously [32,37,38]. In both techniques, the conventional peroxidase-antiperoxidase method was used with horseradish peroxidase and diaminobenzidine/ H 2 O 2 for visualization of the specifically bound probes.…”