Histoplasma capsulatum modulates the acidification of phagolysosomes.

• DOI: 10.1084/jem.177.6.1605
• Publication Date: 2004-06-24T07:56:10Z
• Authors: L G Eissenberg; W E Goldman; P H Schlesinger
• Keywords: Phagolysosome; Zymosan; Histoplasma

The phagolysosome is perhaps the most effective antimicrobial site within macrophages due both to its acidity and variety of hydrolytic enzymes. Few species pathogens survive multiply in these vesicles. However, one strategy for microbial survival would be induce a higher pH organelles, thus interfering with activity many lysosomal Altering intravesicular milieu might also profoundly influence antigen processing, drug delivery, activity. Here we report first example an organism proliferating phagolysosomes that maintain relatively neutral sustained period time. We inoculated P388D1 fluorescein isothiocyanate (FITC)-labeled Histoplasma capsulatum or zymosan. Using ratio fluorescence excitations at 495 450 nm, determined vesicles containing either virulent avirulent FITC-labeled H. yeasts had two units than zymosan methanol-killed capsulatum. difference remained stable least 5.5 h postinoculation. Longer-term studies using cells preincubated acridine orange indicated live continued 30 h. Many agents raise multiple same cell. In contrast, affects only which it located; during coinoculation unlabeled labeled zymosan, organelles still acidified normally. Similarly, no on elevated housing Histoplasma. Thus, were segregated into separate responded independently their phagocytized contents. This localized effect reflect intrinsic between phagosomes particle types, active buffering by microbe, altered ion transport across phagolysosomal membrane such acidification inhibited.