Effects of neutrophils and in vitro oxidants on survival and phenotypic switching of Candida albicans WO-1.

The relationship to pathogenesis of the spontaneous phenotypic switching of Candida albicans is uncertain. Since neutrophils are critical in containment of disseminated candidiasis, we used these cells and some of their potentially microbicidal oxidative products to define effects on a C. albicans strain (WO-1) that exhibits characteristic, easily recognized switching between the white and opaque phenotypes.

Natural inhibitor from Candida albicans blocks release of azurophil and specific granule contents by chemotactic peptide-stimulated human neutrophils.

A product released by Candida albicans hyphae which was previously determined to block the neutrophil respiratory burst also inhibited the degranulation response elicited by the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP). When neutrophils were incubated with 100 micrograms of this Candida hyphal inhibitory product (CHIP) per ml and stimulated with 1,000 nM FMLP, release of the azurophil granule marker beta-glucuronidase and the specific granule marker lactoferrin was decreased to 31.2 +/- 5.

Stimulation of neutrophil actin polymerization and degranulation by opsonized and unopsonized Candida albicans hyphae and zymosan.

We previously showed that unopsonized Candida albicans hyphae stimulated a delayed rise in the putative neutrophil second messengers Ca2+ and inositol 1,4,5-trisphosphate and subsequent O2- release, as compared with opsonized hyphae or zymosan. Therefore, cytoskeletal and degranulation temporal responses to these stimuli were examined. Unopsonized zymosan elicited no neutrophil responses under the experimental condition used.

Candidacidal activity of macrophages from three mouse strains as demonstrated by a new method: neutral red staining.

A new method for assessing the candidacidal activity of macrophages utilizing neutral red stain gave results comparable to well established vital staining methods, methylene blue and acridine orange, and to the absence of germ tube formation of Candida albicans. Dead yeast cells are uniformly stained red while viable yeast cells are unstained except for a red stained vacuole. This assay was used to demonstrate the difference in candidacidal activity between resident and in vivo stimulated peritoneal macrophages of CBA/J, BALB/c and CFW mice.

The effects of soluble Saccharomyces cerevisiae mannan on the phagocytosis of Candida albicans by mouse peritoneal macrophages in vitro.

Saccharomyces cerevisiae mannan inhibited the phagocytic activity and phagocytic capacity of mouse peritoneal macrophages elicited by Concanavalin A (Con A) for Candida albicans yeast cells that were either unopsonized or opsonized with C3. The mannan had no effect on the phagocytosis of C. albicans opsonized with normal human serum or immunoglobulins.