Table 2. Characteristics of P. falciparum infectivity of human hepatocytes in vitro. ND, not determined.
NF54NF135.C10NF166.C8
Experiment B1Day 2#Schizonts per well*1,100 (1,091 to 1,158)2,420 (2,273 to 2,595)2,479 (1,727 to 3,005)
Schizont Ø (μm)3.0 (2.3 to 4.1)3.4 (0.9 to 4.5)2.8 (1.8 to 3.6)
#Nuclei per well18,533 (15,187 to 20,077)20,090 (17,823 to 26,446)17,980 (15,731 to 25,785)
#Nuclei/schizont§16.88.37.3
Day 6#Schizonts per well*1,383 (1,289 to 1,398)2,840 (2,656 to 3,276)2,843 (2,692 to 2,993)
Schizont Ø (μm)11.2 (9.0 to 13.5)18.3 (12.5 to 25.0)16.1 (8.9 to 26.8)
#Nuclei per well56,181 (52,810 to 69,893)216,449 (181,107 to 313,381)248,961 (201,453 to 394,328)
#Nuclei per schizont§40.676.287.6
Multiplication rate||2.49.212.1
Experiment B2Day 2#Schizonts per well*373 (320 to 458)902 (275 to 1,575)1,098 (1,059 to 1,137)
Schizont Ø (μm)1.7 (0.9 to 3.6)2.8 (1.8 to 5.4)3.4 (1.8 to 7.1)
#Nuclei per well8,858 (7,226 to 9,585)16,726 (10,228 to 16,726)21,968 (20,742 to 23,195)
#Nuclei per schizont§23.818.520.0
Day 6#Schizonts per well*1,061 (826 to 124)813 (492 to 1,134)
Schizont Ø (μm)11.4 (6.3 to 16.1)18.9 (12.5 to 28.6)12.5 (8.9 to 17.0)
#Nuclei per well95,295 (94,347 to 11,184)382,508 (364,489 to 451,483)ND
#Nuclei per schizont§218361ND
Multiplication rate||11.519.4ND

*Number of liver-stage schizonts per well, counted by immunofluorescence microscopy after staining with anti-HSP70 MAbs, as in Fig. 2. Data represent median (range) across triplicate wells.

†Schizont diameters, as measured by immunofluorescence microscopy and digital image analysis. Data represent mean (range) of n = 19 to 49 schizonts per sample. NF135.C10 schizonts were larger than NF54 schizonts at day 2 (P < 0.05) and day 6 (P < 0.001) in both experiments and were also larger than NF166.C8 schizonts (P < 0.05 to P < 0.001 in all comparisons except experiment B2, day 2); NF166.68 schizonts were larger than NF54 schizonts at day 2 in experiment B2 (P < 0.001) and at day 6 in experiment B1 (P < 0.001). P values by one-way ANOVA with Tukey’s posttest.

‡Number of parasite nuclei per well, as determined by qPCR; data represent median (range) of triplicate wells.

§Number of nuclei per schizont, as calculated by dividing the median #nuclei per well by the median #schizonts per well.

||Fold increase in number of nuclei per infected human hepatocyte from day 2 to day 6 after infection, as calculated by dividing the median #nuclei per schizont at day 6 after infection by that at day 2.