Identification of constituents of human neutrophil azurophil granules that mediate fungistasis against Histoplasma capsulatum.
Previously we demonstrated that human neutrophils mediate potent and long-lasting fungistasis against Histoplasma capsulatum yeasts and that all of the fungistatic activity resides in the azurophil granules. In the present study, specific azurophil granule constituents with fungistatic activity were identified by incubation with H. capsulatum yeasts for 24 h and by quantifying the subsequent growth of yeasts via the incorporation of [(3)H]leucine. Human neutrophil defensins HNP-1, HNP-2, and HNP-3 inhibited the growth of H. capsulatum yeasts in a concentration-dependent manner with maximum inhibition at 8 microg/ml. At a concentration of 4 microg/ml, all possible paired combinations of defensins exhibited additive fungistatic activity against H. capsulatum yeasts. Cathepsin G and bactericidal-permeability-increasing protein (BPI) also mediated fungistasis against H. capsulatum in a concentration-dependent manner. The fungistatic activities of combinations of cathepsin G and BPI were additive, as were those of combinations of cathepsin G or BPI with HNP-1, HNP-2, and HNP-3. Lysozyme and elastase exhibited modest antifungal activity, and azurocidin and proteinase 3 exhibited no significant fungistasis against H. capsulatum yeasts. Thus, defensins, cathepsin G, and BPI are the major anti-H. capsulatum effector molecules in the azurophil granules of human neutrophils.
Newman
S L
SL
Department of Medicine, Division of Infectious Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA. newmansl@email.uc.edu
Gootee
L
L
Gabay
J E
JE
Selsted
M E
ME
D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins / Q000494:pharmacology*; D002352:Carrier Proteins / Q000494:pharmacology; D056649:Cathepsin G; D002403:Cathepsins / Q000494:pharmacology*; D003594:Cytoplasmic Granules / Q000737:chemistry* / Q000276:immunology; D023082:Defensins / Q000494:pharmacology*; D006658:Histoplasma / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D008565:Membrane Proteins; D008826:Microbial Sensitivity Tests; D009113:Muramidase / Q000494:pharmacology; D053146:Myeloblastin; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D010196:Pancreatic Elastase / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000494:pharmacology
C062991:AZU1 protein, human; D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D002352:Carrier Proteins; D023082:Defensins; D008565:Membrane Proteins; C021623:bactericidal permeability increasing protein; D009113:Muramidase; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D053146:Myeloblastin