Carbohydrate analysis of porcine thyroglobulin isoforms with different iodine contents

Thyroglobulin specific IgE and a possible link to suspected penicillin induced allergic skin manifestations - cross sectional study

Porcine thyroglobulin was important in the discovery of alpha-Gal allergy. Here the linkage of porcine thyroglobulin specific IgE with IgE positivity to routinely assessed allergens and to the incoming diagnosis within a population of suspected atopic individuals is explored. IgE, IgA, total IgG and IgG subclasses to porcine thyroglobulin, IgE to bovine, human thyroglobulin and meat extract were measured with ELISA. The following correlations were observed in IgE binding to porcine and bovine thyroglobulin (r=0.910, p=1x10-17), porcine and human thyroglobulin (r= 0.635, p=4x10-6), human and bovine thyroglobulin (r=0.746, p=6x10-9) and porcine thyroglobulin and meat extract (r=0.482, p=0.0009). Only one out of ten samples which showed binding to porcine thyroglobulin in ELISA tested positive with ImmunoCAP alpha-Gal, implying different epitope/s. Increased IgE binding was detected towards a more electronegative fraction of porcine thyroglobulin separated according to charge and the binding could be partially inhibited by galactose. Anti-thyroglobulin IgE was found in 29.7% of the population, in subjects who were significantly younger, p<0.0001 and it occurred more frequently in patients referred for testing penicillin specific IgE (OR 2.48, p=0.0059) and were negative. IgE specific to porcine, bovine and possibly human thyroglobulin may be implicated in post-infectious skin manifestation misinterpreted as penicillin allergy.

Nanoparticle decorated surfaces with potential use in glycosylation analysis

A majority of all biologically active proteins are glycosylated and various diseases have proven to correlate with alterations in protein glycosylation. Sensitive identification of different glycoprotein glycoforms is therefore of great diagnostic value. Here we describe a method with potential for glycoprotein profiling, based on lectins as capture probes immobilized on particulate substrates in the nm-range. The nanoparticles present high concentrations of attachment sites for specific ligands and cause minimal steric hindrance to binding. In the present model study the mannose-binding lectin ConA has been coupled to polystyrene nanoparticles via a poly(ethyleneoxide) linker which protects the protein conformation and activity and prevents unspecific protein adsorption. The ConA-coated particles are accommodated at different spots on the analytical surface via oligonucleotide linkage. This attachment, which relies on the hybridization of complementary oligonucleotides, allows firm fixation of the particles at specific positions. The ConA attached to the particles has retained conformation and activity and binds selectively to a series of different glycoproteins. The results indicate the potential for using a multi-lectin nanoparticle array in glycoprotein mapping.

Sialic acid expression in autoimmune thyroiditis

Autoimmune diseases of the thyroid gland are among the most frequent endocrine disorders. The present study analyzes expression patterns of sialic acids in these diseases. Three lectins specific for sialic acids were used for the histochemical analysis of surgical specimens of the thyroid gland: Tritrichomonas mobilensis lectin that stains all types of sialic acids, Maackia amurensis leukoagglutinin that stains sialic acids with alpha2,3 linkage and Sambucus nigra agglutinin that stains sialic acids with alpha2,6 linkage. In autoimmune thyroiditis, there was a significant increase in sialic acid expression in epithelial cells, especially on luminal membranes of follicular cells. The alpha2,3 linkage dominated over the alpha2,6 linkage. Lymphocytes of patients with Hashimoto thyroiditis, especially in germinal centers, showed strong expression of alpha2,6-linked sialic acids on their cell membrane. Vascular endothelium was positive in all specimens. It can be concluded, that there is a significant increase in sialic acid expression in autoimmune diseases of the thyroid gland, predominantly of sialic acids with alpha2,3 linkage, whereas the sialylation pattern of lymphocytes in Hashimoto thyroiditis was also different.

Changes of oligosaccharides and fatty acids in monkey hippocampus by synaptic potentiation

We measured the release of free fatty acids and structural changes of glycoprotein glycans induced by tetraethylammonium (TEA) salt in hippocampal slices of cynomolgus monkey brain. The release of free fatty acids in the hippocampal slices occurred after synaptic potentiation by TEA in a different manner from rat hippocampus. Arachidonic acid release in monkey hippocampus occurred much faster than that in rat. Several types of glycans of monkey hippocampal glycoproteins were determined depending on the duration time after TEA treatment. 5-Mannose was increased within 2 min, while polysialoglycans were increased after 5 min or later. Comparative study of glycans of monkey and rat hippocampal slices revealed the presence of relatively larger amount of sialo- and multi-anntenary glycans in rat than in monkey. These results indicate that the depolarizing stimulation of monkey hippocampal slices induced the change of glycoprotein glycan structures and release of free fatty acids in a different manner from rat hippocampus.