Biomaterial Database

Lysosomal enzyme release from human monocytes by particulate activators is mediated by beta-glucan inhibitable receptors. 1987

M J Janusz, and K F Austen, and J K Czop

Human peripheral blood monocytes ingest particulate activators and generate leukotrienes via a trypsin-sensitive, beta-glucan-inhibitable receptor. The incubation of monolayers of monocytes with from 4 X 10(5) to 2 X 10(8) zymosan or glucan particles resulted in a dose-dependent release of up to 9% +/- 1.9 and 17.8% +/- 5.3 (mean +/- SD, n = 3) of the lysosomal enzyme, N-acetylglucosaminidase, into the culture medium. Lysosomal enzyme release occurred throughout the 2-hr period studied, with the greatest rate of N-acetyl-glucosaminidase release occurring during the first hour; the presence of 5 micrograms/ml of cytochalasin B accelerated this process when zymosan was the agonist. The preincubation of monocytes with from 0.5 to 500 micrograms/ml of soluble yeast beta-glucan inhibited N-acetylglucosaminidase release by 4 X 10(7) zymosan and glucan particles in a dose-dependent manner, with 50% inhibition occurring with 50 micrograms/ml of soluble yeast beta-glucan (mean +/- SD, n = 3). Preincubation with as much as 5 mg/ml of yeast mannan had no inhibitory effect on N-acetylglucosaminidase release. The pretreatment for 30 min of monolayers of monocytes with 50 micrograms/ml of affinity-purified trypsin, which selectively inactivates the monocyte-phagocytic response to particulate activators, also fully inhibited lysosomal enzyme release induced by zymosan and glucan particles. The inhibitory effects of a soluble ligand, yeast beta-glucan, and of trypsin pretreatment on lysosomal enzyme release correspond to the inhibitory effect of these agents on monocyte phagocytosis of zymosan and glucan particles and thus indicates ligand specificity for the beta-glucan receptor in the release of stored intracellular mediators.

UI	MeSH Term	Description	Entries
D008247	Lysosomes	A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured or undergoes MEMBRANE FUSION. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed).	Autolysosome,Autolysosomes,Lysosome
D009000	Monocytes	Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.	Monocyte
D010587	Phagocytosis	The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).	Phagocytoses
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D011971	Receptors, Immunologic	Cell surface molecules on cells of the immune system that specifically bind surface molecules or messenger molecules and trigger changes in the behavior of cells. Although these receptors were first identified in the immune system, many have important functions elsewhere.	Immunologic Receptors,Immunologic Receptor,Immunological Receptors,Receptor, Immunologic,Receptors, Immunological
D003170	Complement Pathway, Alternative	Complement activation initiated by the interaction of microbial ANTIGENS with COMPLEMENT C3B. When COMPLEMENT FACTOR B binds to the membrane-bound C3b, COMPLEMENT FACTOR D cleaves it to form alternative C3 CONVERTASE (C3BBB) which, stabilized by COMPLEMENT FACTOR P, is able to cleave multiple COMPLEMENT C3 to form alternative C5 CONVERTASE (C3BBB3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.	Alternative Complement Pathway,Properdin Pathway,Alternative Complement Activation Pathway,Complement Activation Pathway, Alternative
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D005936	Glucans	Polysaccharides composed of repeating glucose units. They can consist of branched or unbranched chains in any linkages.	Glucan,Polyglucose,Polyglucoses,Glucan (BO),Glucose Polymer,Polycose,Polymer, Glucose
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000118	Acetylglucosaminidase	A beta-N-Acetylhexosaminidase that catalyzes the hydrolysis of terminal, non-reducing 2-acetamido-2-deoxy-beta-glucose residues in chitobiose and higher analogs as well as in glycoproteins. Has been used widely in structural studies on bacterial cell walls and in the study of diseases such as MUCOLIPIDOSIS and various inflammatory disorders of muscle and connective tissue.	N-Acetyl-beta-D-glucosaminidase,Chitobiase,N,N-Diacetylchitobiase,N-Ac-beta-Glucosaminidase,NAGase,beta-D-Acetamido-2-Deoxyglucosidase,beta-D-N-acetylglucosaminidase,beta-N-Acetylglucosaminidase,N Ac beta Glucosaminidase,N Acetyl beta D glucosaminidase,N,N Diacetylchitobiase,beta D Acetamido 2 Deoxyglucosidase,beta D N acetylglucosaminidase,beta N Acetylglucosaminidase