Linked Life Data

3711662

Source:http://linkedlifedata.com/resource/pubmed/id/3711662

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
1986-7-7
pubmed:abstractText
The pathogenic protozoan Leishmania donovani must gain entrance into mononuclear phagocytes to successfully parasitize man. The parasite's extra-cellular promastigote stage is ingested by human peripheral blood monocytes or monocyte-derived macrophages in the absence of serum, in a manner characteristic of receptor-mediated endocytosis. We have found remarkable similarities between the macrophage receptor(s) for promastigotes and a previously characterized eucaryotic receptor system, the mannose/fucose receptor (MFR), that mediates the binding of zymosan particles and mannose- or fucose-terminal glycoconjugates to macrophages. Ingestion of promastigotes by monocyte-derived macrophages was inhibited by several MFR ligands. Mannan (2.5 mg/ml) decreased ingestion by 63.7% (p less than 0.001), and the neoglycoproteins mannose-BSA and fucose-BSA (20 micrograms/ml) inhibited parasite ingestion by 46.5% and 39.6%, respectively (p less than 0.04). In contrast, promastigote ingestion by monocytes was unaffected by MFR ligands. These results are consistent with reports that MFR activity is present in monocyte-derived macrophages but not in monocytes. Furthermore, attachment of promastigotes to macrophages, assessed by using cytochalasin D to prevent phagocytosis, was reduced 49.8% by mannan. Reorientation of the MFR to the ventral surface of the cell was achieved by plating macrophages onto mannan-coated coverslips, reducing MFR activity on the exposed cell surface by 94% as assessed by binding of 125I-mannose-BSA. Under these conditions, ingestion of promastigotes was inhibited by 71.4% (p less than 0.006). Internalization of the MFR by exposure of macrophages to zymosan before infection with promastigotes resulted in a 62.3% decrease in parasite ingestion (p less than 0.006). Additionally NH4Cl, a weak lysosomotropic base that impairs MFR recycling, decreased macrophage ingestion of promastigotes by 38.2% (p less than 0.03, 30 mM NH4Cl). Subinhibitory concentrations of NH4Cl (10 mM) and of mannan (0.25 mg/ml) together inhibited parasite ingestion by 76.4% (p less than 0.002). These studies suggest that L. donovani promastigotes may utilize a receptor system on human monocyte-derived macrophages, the MFR, to efficiently parasitize the human host.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Ammonium Chloride, http://linkedlifedata.com/resource/pubmed/chemical/Lectins, C-Type, http://linkedlifedata.com/resource/pubmed/chemical/Mannans, http://linkedlifedata.com/resource/pubmed/chemical/Mannose, http://linkedlifedata.com/resource/pubmed/chemical/Mannose-Binding Lectins, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Cell Surface, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Immunologic, http://linkedlifedata.com/resource/pubmed/chemical/Serum Albumin, http://linkedlifedata.com/resource/pubmed/chemical/Serum Albumin, Bovine, http://linkedlifedata.com/resource/pubmed/chemical/Trypsin, http://linkedlifedata.com/resource/pubmed/chemical/mannose receptor, http://linkedlifedata.com/resource/pubmed/chemical/mannose-bovine serum albumin...
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
136
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4681-8
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Evidence that Leishmania donovani utilizes a mannose receptor on human mononuclear phagocytes to establish intracellular parasitism.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't