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G Zenke

Publications and source records attributed to G Zenke.

38 records · Page 3Linked to original sources

Characterization of minor and major idiotopes associated with human antibodies to N-acetyl-D-glucosamine.

Human antibodies to N-acetyl-D-glucosamine (GlcNAc) were analysed by conventional and monoclonal antiidiotypic antibodies. These were prepared to the antibody secreted by the human lymphoblastoid cell line B17 and to the antibody isolated from an individual serum containing a prominent clonotype 1A, both with specificity for GlcNAc. Idiotypes and idiotopes associated with these antibodies have the following properties: 1) their frequency of expression in the human population varies between rare (approximately 1.5%) and frequent (greater than 80%); 2) they have a high degree of association with antibody specificity for GlcNAc (50-100%); 3) each idiotope appears to be expressed independently of others; 4) one idiotope may be associated with a variety of clonotypes; and 5) idiotopes can be identified which are both frequently expressed in the population and associated with major proportions of the antibodies in single individuals. These latter idiotopes may be useful for studies on the modulation of human immune responses by antiidiotypic antibodies.

Acetylglucosamine↗

Nephrotoxicity of cyclosporin A and FK506: inhibition of calcineurin phosphatase.

Cyclosporin A (CsA; 50 mg/kg) and Fujimycine (FK506; 5 mg/kg), but not the related macrolide immunosuppressant rapamycin (5 mg/kg), caused a reduction of glomerular filtration rate, degenerative changes of proximal tubular epithelium, and hypertrophy of the juxtaglomerular apparatus in male Wistar rats when given for 10 days. The molecular mechanisms of CsA and FK506 toxicity were investigated. Cyclophilin A and FK506-binding protein, the main intracytoplasmic receptors for CsA and FK506, respectively, were each detected in renal tissue extract. In the kidney, high levels of immunoreactive and enzymatically active calcineurin were found which were inhibited by the immunosuppressants CsA and FK506, but not by rapamycin. Finally, specific immunophilin-drug-calcineurin complexes formed only in the presence of CsA and FK506, but not rapamycin. These results suggest that the nephrotoxic effects of CsA and FK506 is likely mediated through binding to renal immunophilin and inhibiting calcineurin phosphatase.

Animals↗