ABSTRACT
Aminosugars have a good affinity for the NKR-P1A protein, the major activating receptor at the surface of rat natural killer cells. We have systematically investigated the structural requirements of the recombinant soluble dimeric form of the receptor for its optimal carbohydrate ligands. While N-acetylD-mannosamine was the best neutral monosaccharide ligand, its participation in the context of an extended oligosaccharide sequence was equally important. The IC(50) value for the GalNAcbeta1 --> ManNAc disaccharide was nearly 10(-10) M with a further possible increase depending on the type of the glycosidic linkage and the aglycon nature. From the point of view of its availability, stability, and affinity for the receptor and a potential in vivo use, these studies are pivotal for the design of an oligosaccharide or glycomimetics suitable for further clustering into the multivalent glycodendrimers.
Subject(s)
Antigens, Surface/metabolism , Lectins, C-Type , Oligosaccharides/pharmacology , Animals , Antigens, Surface/chemistry , Antigens, Surface/drug effects , Antigens, Surface/genetics , Carbohydrate Conformation , Carbohydrates/chemistry , Killer Cells, Natural/drug effects , Killer Cells, Natural/metabolism , NK Cell Lectin-Like Receptor Subfamily B , Oligosaccharides/chemistry , Protein Folding , Rats , Recombinant Proteins/chemistry , Recombinant Proteins/drug effects , Recombinant Proteins/metabolism , Structure-Activity RelationshipABSTRACT
NKR-P1 protein is an important activating receptor at the surface of the rat natural killer cells. GlcNAc and chitooligomers were identified as strong activation ligands in vitro and in vivo. Their clustering brings about increase of their affinity to the NKR-P1 by 3-6 orders. Here we describe novel methodology for preparation of neoglycoproteins based on BSA carrying the chitooligomers (n = 2-5). Further on we developed novel methodology of the coupling of glycosylamines via aromatic-SCN activated linker both to protein or synthetic cores. Inhibition studies of chitooligomer glycoconjugates with the NKR-P1 receptor show that our neoglycoproteins are very strong ligands with high binding affinity (-log IC(50) = 13-15). In analogy with our previous observations with GlcNAc clustered on protein or PAMAM backbones the synthetic chitooligomer clusters should provide considerably better ligands in the in vivo antitumor treatment.
Subject(s)
Antigens, Surface/metabolism , Glycoproteins/chemical synthesis , Glycoproteins/metabolism , Killer Cells, Natural/metabolism , Lectins, C-Type/metabolism , Amines/chemistry , Animals , Cattle , Chitin/chemistry , Chromatography/methods , Immunoblotting , Inhibitory Concentration 50 , Isothiocyanates/chemistry , Ligands , N-Acetylneuraminic Acid/metabolism , NK Cell Lectin-Like Receptor Subfamily B , Nuclear Magnetic Resonance, Biomolecular , Protein Binding , Rats , Serum Albumin, Bovine/chemistry , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Thioglycosides/chemical synthesisABSTRACT
A nursing information systems task force at the Hospital of the University of Pennsylvania developed a user classification scheme to assign access privileges to their personnel. By implementing this process, hospital administrators can ensure that their computer access policy protects the patient's privacy while allowing the availability of necessary information to the appropriate personnel.
