ABSTRACT
beta-Glucans are polysaccharides that act as nonspecific immune system stimulants. However, many beta-Glucans are sparingly soluble in water. This work describes an oxidative procedure, which solubilizes the beta-Glucan from Saccharomyces cerevisiae and maintains its immunostimulatory properties. Furthermore, the carboxylates at the site of oxidation allow for the conjugation of small molecule immunostimulants. Both the parent oxidized beta-glucan and its conjugates with O-beta-alanyl-5-[6-(N,N'-dimethylamino)purin-9-yl]pentanol stimulate cytotoxic T-lymphocytes (CTLs), B cells and macrophages. In addition, they both stimulate natural killer (NK) cells, a property which the small molecule purine does not possess.
Subject(s)
Adjuvants, Immunologic/chemistry , Adjuvants, Immunologic/pharmacology , Glucans/chemistry , Glucans/pharmacology , Adjuvants, Immunologic/isolation & purification , Animals , B-Lymphocytes/drug effects , B-Lymphocytes/immunology , Carbohydrate Sequence , Female , Glucans/isolation & purification , Humans , In Vitro Techniques , Killer Cells, Natural/drug effects , Killer Cells, Natural/immunology , Macrophages/drug effects , Macrophages/immunology , Mice , Mice, Inbred C57BL , Molecular Sequence Data , Oxidation-Reduction , Saccharomyces cerevisiae/chemistry , T-Lymphocytes, Cytotoxic/drug effects , T-Lymphocytes, Cytotoxic/immunologyABSTRACT
Polymers containing covalently attached 18-crown-6 or 2.2.2 cryptand units were incorporated into plasticized PVC membranes and the composite membranes were examined as potassium ion sensor elements. Ionophores were linked to carboxy-PVC and to poly(acrylic acid) via amide linkages to an alkyl spacer unit. Coated-wire electrodes (CWEs) from the immobilized ionophores gave acceptable responses, but conventional ion-selective membrane electrodes (ISEs) prepared by solvent casting were inactive. Dip-cast membranes did give active ISEs. Potassium electrode performance was independent of the loading of the ionophore within the acrylate support polymer, but depended upon the spacer length. Ion selectivity varied with the ionophore loading within the support polymer. Selectivity is a composite of the ionophore selectivity and ion-exchange interactions with the acrylate backbone, giving selectivities akin to carboxylate substituted crown ethers, notably enhanced monovalent/divalent ion discrimination relative to the ionophore in solution. Polymer immobilization extended the lifetime of active electrodes.
