Table 1.

Erythrophagocytosis, hemolytic activity, and cysteine proteinase activity in axenic and monoxenic trophozoites of E. histolytica

StrainaErythrophagocytosis (HRBC/amebae)bHemolytic activity (OD570)cProtease activity (U)d
HK-9 axenic7.9 ± 1.20.91 ± 0.0579.0 ± 8.7
HK-9 (EcO55)3.5 ± 1.10.22 ± 0.0315.5 ± 3.8
HK-9 (Ec346)7.5 ± 0.90.94 ± 0.0519.1 ± 4.0
HM-1 axenic11.9 ± 1.90.69 ± 0.0320.5 ± 3.6
HM-1 (EcO55)9.5 ± 1.10.72 ± 0.0423.2 ± 4.5
HM-1 (Ec346)12.2 ± 2.10.75 ± 0.0618.8 ± 4.9
  • a E. histolytica grown under axenic conditions or in monoxenic culture with E. coli (Ec) serotype O55 or 346 for 1 month.

  • b Erythrophagocytosis rates (± standard deviation) of E. histolyticatrophozoites after 15 min of incubation at 37°C in a ratio of 1:100 (amebae-HRBC).

  • c Hemolytic activity (± standard deviation) ofE. histolytica after 90 min of incubation with HRBC in a ratio of 1:2,000 (amebae-HRBC). OD570, optical density at 570 nm.

  • d Cysteine proteinase activity (± standard deviation) measured as micromoles of substrate (Z-Arg-Arg-pNA) digested per minute per milligram of protein (U).