Fig. 7
Bioluminescence imaging of P. berghei blood stages. a Luminescence values from various concentrations of iRBCs from PbNLuc- and PbFluc-infected mice, ranging from 1 to 10,000 iRBCs (values shown in logarithmic scale). b Ratio of luminescence of PbNLuc iRBCs compared to PbFLuc iRBCs showing a 150-fold higher signal. 1000 parasites were isolated from a drop of blood of synchronously infected mice at 18 h post-infection. The value for PbFLuc luminescence was set to a value of 1, and the value of PbNLuc luminescence expressed in relation to the PbFLuc value. c, d Parasitaemia curve as measured by bioluminescence, in Balb/c and C57BL/6 mice. 9 Balb/c and C57BL/6 mice were infected with 105 parasites, and their parasitaemia followed daily. At every time post-infection, 20μl of blood were taken by tail vein puncture, and luminescence was assessed; c shows representative images of 5 mice followed in (d). e Correlation between parasitaemia and luminescence at various times post-infection and various parasite burdens. Following injection of 105 parasites into mice, 25 μl of blood were obtained by tail vein puncture for measurement either by luminescence (x-axis) or Giemsa stain of thin blood smears from which parasitaemia was quantified using a light microscope (y-axis). f Bioluminescence signal from PbNLuc synchronous infections. 106 schizonts were injected into C57BL/6 mice, and 20 μl of blood collected bi-hourly from 9 to 27 h post-infection, showing sequestration from 18 to 25 h post-infection. g Bioluminescence signal from blood of PbNLuc and PbFLuc co-infected mice, as measured bi-hourly from 9 to 27 h post-synchronous infections, showing marked schizont sequestration of both parasite lines from 18 to 25 h. h Graphical representation of a limiting dilution leading to isolation of single parasites. The graph shows 5.5 % positivity. [***p < 0.001; error bars in all graphs represent standard deviations (SD)]