Entamoeba histolytica: differences in phagosome acidification and degradation between attenuated and virulent strains.
Phagocytosis is the important virulent determinant of the enteric protozoan parasite Entamoeba histolytica. We compared the kinetics of phagosome maturation of attenuated and highly-virulent strains of E. histolytica using video microscopy. Phagosomes of attenuated strains were acidified rapidly within 2 min after phagosome formation (at the rate of 0.96 pH/min), persisted at pH 4.46+/-0.13, and degraded ingested GFP-Leishmania very efficiently (90-94% GFP fluorescence was lost in 30 min), while phagosomes of highly-virulent strains were acidified slowly (0.69 pH/min), persisted at 5.11+/-0.23, and degraded GFP less efficiently (60-71% decrease). These results suggest that efficiency of phagosome maturation is most probably inversely correlated with apparent virulence.
Department of Parasitology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-851, Japan.
Biswa Nath
BN
Mitra
Seiki
S
Kobayashi
Yumiko
Y
Saito-Nakano
Tomoyoshi
T
Nozaki
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004748:Entamoeba histolytica / Q000276:immunology / Q000472:pathogenicity*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007891:Leishmania / Q000276:immunology / Q000378:metabolism; D008647:Mesocricetus; D018715:Microscopy, Video; D010587:Phagocytosis / Q000502:physiology; D010588:Phagosomes / Q000378:metabolism*; D014774:Virulence
D049452:Green Fluorescent Proteins