DIFFERENT SUSCEPTIBILITIES OF YEASTS AND CONIDIA OF PENICILLIUM-MARNEFFEI TO NITRIC-OXIDE (NO)-MEDIATED FUNGICIDAL ACTIVITY OF MURINE MACROPHAGES

Citation
N. Kudeken et al., DIFFERENT SUSCEPTIBILITIES OF YEASTS AND CONIDIA OF PENICILLIUM-MARNEFFEI TO NITRIC-OXIDE (NO)-MEDIATED FUNGICIDAL ACTIVITY OF MURINE MACROPHAGES, Clinical and experimental immunology, 112(2), 1998, pp. 287-293
Citations number
48
Categorie Soggetti
Immunology
ISSN journal
00099104
Volume
112
Issue
2
Year of publication
1998
Pages
287 - 293
Database
ISI
SICI code
0009-9104(1998)112:2<287:DSOYAC>2.0.ZU;2-A
Abstract
Penicillium marneffei is an important opportunistic fungal pathogen. H ost defence mechanisms against P. marneffei are not fully understood. We investigated the fungicidal activity of murine peritoneal macrophag es against two forms of P. marneffei, conidia and yeast cells, and the involvement of the NO-mediated killing system. Peritoneal macrophages suppressed the intracellular, growth of P. marneffei yeast cells and conidia. The number of live yeast cells within macrophages was signifi cantly reduced by activation of macrophages by interferon-gamma (IFN-g amma), while a similar response was not observed with conidia. IFN-gam ma-induced macrophage fungicidal activity against yeast cells was medi ated by NO and was almost completely inhibited by N-G-monomethyl-L-arg inine (L-NMMA), a competitive inhibitor of NO synthesis, while N-G-mon omethyl-D-arginine (D-NMMA), an optical isomer of L-NMMA, did not show any influence. NO production by macrophages stimulated with IFN-gamma was significantly enhanced when these macrophages were cultured with P. marneffei yeast cells, while conidia did not enhance macrophage NO production. Furthermore, yeast cells were more susceptible to the kill ing effect of chemically generated NO than conidia. Our results indica te that the yeast form of P. marneffei is more sensitive to the fungic idal activity of IFN-gamma-stimulated macrophages than conidia, and su ggest that the different effects of two forms of P, marneffei on macro phage NO production and their different susceptibilities to NO may be reasons for the present findings.