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. 2021 Jul 12;16(7):e0254498. doi: 10.1371/journal.pone.0254498

Fig 1. Sporozoite infectivity of chimeric P. berghei lines expressing P. falciparum proteins.

Fig 1

Sporozoite infectivity is determined by measuring parasite liver load by in vivo imaging of luciferase-expressing liver stages at 44 hours post injection (hpi) of either 1x103 or 1x104 sporozoites and by measuring the day to blood stage patency, i.e. the day to reach 1% parasitemia. The Kaplan-Meier curves illustrate the prepatent period. Data shown from groups of 3–5 mice. (A) Chimeric P. berghei lines that showed WT-like infectivity in mice. a) Representative in vivo imaging (IVIS) of bioluminescence at 44 hpi shown in the livers of OF1 mice infected with 1x103 chimeric P. berghei sporozoites of HT, SIAP2, and RPL3. b) Parasite liver loads in mice infected with chimeric P. berghei sporozoites of HT, SIAP2 and RPL3 expressed as relative luminescence units (RLU). Significance of RLU values (Mann-Whitney test): HT—0.0159, SIAP2–0.0159 and RPL3–0.0159. c) The Kaplan-Meier curve showing the prepatent period of HT, SIAP2 and RPL3 chimeric sporozoites. Significance values of day to patency [Log-Rank (Mantel-Cox) test]: n.s. d) Representative in vivo imaging (IVIS) of bioluminescence at 44 hpi shown in the livers of OF1 mice infected with 1x104 chimeric P. berghei sporozoites of SPELD, SPATR and ETRAMP10.3. e) Parasite liver loads in mice infected with chimeric P. berghei sporozoites of SPELD, SPATR and ETRAMP10.3 expressed as relative luminescence units (RLU). Significance of RLU values (Mann-Whitney test): SPELD, SPATR and ETRAM10.3: not significant (n.s). e) The Kaplan-Meier curve showing the prepatent period of SPELD, SPATR and ETRAM10.3 chimeric sporozoites. Significance values of day to patency [Log-Rank (Mantel-Cox) test]: n.s. (B) Chimeric P. berghei lines that produced reduced or no sporozoite infectivity compared to WT sporozoites (MAEBL, GEST, SIAP1, SSP3, P36, P52, B9 and SPECT2). a) Representative in vivo imaging (IVIS) of bioluminescence at 44 hpi shown in the livers of OF1 mice infected with 1x103 chimeric P. berghei sporozoites of MAEBL, GEST, SPECT2, SSP3 and B9. b) Parasite liver loads in mice infected with chimeric P. berghei sporozoites of MAEBL, GEST and SPECT2 expressed as relative luminescence units (RLU). Significance of RLU values (Mann-Whitney test): MAEBL—0.0286, GEST (rep)—0.0159 and SPECT2–0.0079. SIAP1, SSP3, P36, P52, B9: no luminescence signal. c) Representative in vivo imaging (IVIS) of bioluminescence at 44 hpi shown in the livers of OF1 mice infected with 1x104 chimeric P. berghei sporozoites of GEST, SSP3, SIAP1, P36, P52 and Pb-PfSPECT1(r). d) The Kaplan-Meier curve showing the prepatent period of MAEBL, GEST, SSP3, SPECT2 and B9 in mice infected with 1x103 chimeric sporozoites (upper panel) and GEST, SSP3, SIAP1, P36, P52, Pb-PfSPECT2(r) and Pb-PfB9(r) in mice infected with 1x104 chimeric sporozoites (lower panel). Significance values of day to patency [Log-Rank (Mantel-Cox) test]: GEST repeat (3/5 mice)– 0.0027, GEST (1/3 mice)– 0.0253 and SSP3 (3/3 mice)– 0.0253. The other chimeric lines did not initiate blood stage infections.