Protein synthesis by phagocytized yeast cells of<i>Histoplasma capsulatum</i>

Howard, Dexter H.; Otto, V

doi:10.1080/00362177085190341

Cited by 6 publications

(7 citation statements)

References 8 publications

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“…H. capsulatum, strain no. 505 (stock culture collection of this Department), which has been employed in experiments previously reported was used in these studies (10). The yeast cell phase was maintained and subcultured as noted in other reports (7,10).…”

Section: Methodsmentioning

confidence: 99%

“…Suspensions of mononuclear cells (MN) were obtained from the peritoneal cavities of unstimulated Webster-Swiss mice. Methods for the harvest and maintenance of such cultures have been published (7,10,11). The tissue culture medium (TCM) was 40% normal human serum (NHS) (Flow Laboratories, Inc., Inglewood, Calif.) in Hanks balanced salt solution (BSS).…”

Section: Methodsmentioning

confidence: 99%

“…Puromycin, which inhibits protein synthesis by many types of cells, does not affect H. capsulatum at certain concentrations, probably because it does get into the fungus cells. Thus, in some studies 20 ,ug of puromycin per ml was incorporated into the pulse medium to impede protein synthesis by the mouse macrophages while permitting uninterrupted synthesis by the yeasts (10).…”

Section: Methodsmentioning

confidence: 99%

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Further Studies on the Inhibition of Histoplasma capsulatum Within Macrophages from Immunized Animals

Howard

1973

Infect Immun

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Mononuclear phagocytes freshly harvested from immunized animals restrict the intracellular growth of Histoplasma capsulatum. The fate of the inhibited fungus is the subject of this report. Macrophages harvested from mice immunized by sublethal infection were parasitized in vitro with yeast cells of H. capsulatum. The subsequent fate of the fungus was assessed by staining characteristics, viability on subculture, and radioisotopic techniques. No tinctorial distinction could be made between yeasts within normal or immune phagocytes stained by the May Greenwald-Giemsa or by the Gridley techniques. Yeast cells recovered after 24 h of residence within the cytoplasm of immune monocytes excluded the dye eosin-Y, germinated on Casamino Acid agar incubated at 30 C, and initiated growth at a normal rate within phagocytes from normal animals. Thus even though the growth of H. capsulatum was inhibited within macrophages from immunized animals, the fungus was not killed by the encounter. However, autoradiographic studies established that protein synthesis by the fungus in situ was impaired.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Further Studies on the Inhibition of Histoplasma capsulatum Within Macrophages from Immunized Animals

Howard

1973

Infect Immun

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“…Guinea pig PMN phagocytes readily engulf yeast cells of the fungus and promptly kill them. In contrast, blastospores of H. capsulatum not only survive within normal MN phagocytes but thrive therein, growing at a rate comparable to that on lifeless media (7) and manufacturing macromolecules unimpeded (8). H. capsulatum is sensitive to a combination of H202, halide, and a peroxidase-like activity derived from PMN granule lysates.…”

Section: Discussionmentioning

confidence: 99%

Fate of Histoplasma capsulatum in Guinea Pig Polymorphonuclear Leukocytes

Howard

1973

Infect Immun

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Guinea pig polymorphonuclear leukocytes (PMN) were parasitized in vitro with yeast cells of Histoplasma capsulatum. Preparations stained after 3 h at 37 C with May Greenwald-Giemsa revealed that 87% of the yeasts were tinctorially altered. Such alterations corresponded to those displayed by fungus cells intentionally killed by heat or other means and thus the altered yeast were presumed to be dead. A combination of 10-5 M H202, 10-5 M KI, and horseradish

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“…The potential importance of MPO as an antimicrobial system has been stressed by numerous investigators in recent years (e.g., in reference 15), although Aspergillus fumigatus is not killed after ingestion by neutrophils (11). Histoplasma capsulatum cells have been found to actually multiply inside human, mouse, and guinea pig histiocytes (8) and engage in protein synthesis after being phagocytized by mouse histiocytes (9).…”

mentioning

confidence: 99%

Intracellular Fate of Cryptococcus neoformans

1972

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Human peripheral leukocytes were found to engulf and kill cells of Cryptococcus neoformans. Fewer encapsulated than nonencapsulated cells met this fate, since cryptococcal capsular polysaccharide inhibited phagocytosis. During 10 to 12 hr of incubation of nonencapsulated cells in human serum, sufficient polysaccharide was produced to inhibit phagocytosis by 50%. The polysaccharide inhibitor was found in the sera of four patients with cryptococcosis, but not on the surfaces of their leukocytes. Additional experiments indicated that serum is not essential for effective phagocytosis. However, normal human serum contains anticryptococcal activity which is not inhibited by capsular material. Preliminary findings indicate that the phagocytic index of a patient with cryptococcosis may be correlated with the severity of his disease.

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Protein synthesis by phagocytized yeast cells ofHistoplasma capsulatum

Cited by 6 publications

References 8 publications

Further Studies on the Inhibition of Histoplasma capsulatum Within Macrophages from Immunized Animals

Further Studies on the Inhibition of Histoplasma capsulatum Within Macrophages from Immunized Animals

Fate of Histoplasma capsulatum in Guinea Pig Polymorphonuclear Leukocytes

Intracellular Fate of Cryptococcus neoformans

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