Complete Plasmodium falciparum liver-stage development in liver-chimeric mice
Ashley M. Vaughan, … , Alexander Ploss, Stefan H.I. Kappe
Ashley M. Vaughan, … , Alexander Ploss, Stefan H.I. Kappe
Published October 1, 2012; First published September 10, 2012
Citation Information: J Clin Invest. 2012;122(10):3618-3628. https://doi.org/10.1172/JCI62684.
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Categories: Technical Advance Infectious disease

Complete Plasmodium falciparum liver-stage development in liver-chimeric mice

Abstract

Plasmodium falciparum, which causes the most lethal form of human malaria, replicates in the host liver during the initial stage of infection. However, in vivo malaria liver-stage (LS) studies in humans are virtually impossible, and in vitro models of LS development do not reconstitute relevant parasite growth conditions. To overcome these obstacles, we have adopted a robust mouse model for the study of P. falciparum LS in vivo: the immunocompromised and fumarylacetoacetate hydrolase–deficient mouse (Fah–/–, Rag2–/–, Il2rg–/–, termed the FRG mouse) engrafted with human hepatocytes (FRG huHep). FRG huHep mice supported vigorous, quantifiable P. falciparum LS development that culminated in complete maturation of LS at approximately 7 days after infection, providing a relevant model for LS development in humans. The infections allowed observations of previously unknown expression of proteins in LS, including P. falciparum translocon of exported proteins 150 (PTEX150) and exported protein-2 (EXP-2), components of a known parasite protein export machinery. LS schizonts exhibited exoerythrocytic merozoite formation and merosome release. Furthermore, FRG mice backcrossed to the NOD background and repopulated with huHeps and human red blood cells supported reproducible transition from LS infection to blood-stage infection. Thus, these mice constitute reliable models to study human LS directly in vivo and demonstrate utility for studies of LS–to–blood-stage transition of a human malaria parasite.

Authors

Ashley M. Vaughan, Sebastian A. Mikolajczak, Elizabeth M. Wilson, Markus Grompe, Alexis Kaushansky, Nelly Camargo, John Bial, Alexander Ploss, Stefan H.I. Kappe

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Figure 1

P. falciparum LS development in FRG huHep mice.

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P. falciparum LS development in FRG huHep mice. Infected liver sectio...
Infected liver sections were assayed by indirect immunofluorescence using antibodies specific to P. falciparum for parasite detection. (A) LSs at day 3 of infection were visualized using antibodies to parasite CSP, which localizes to the parasite surface. (B) LSs at day 5 of infection were visualized with antibodies to EXP-2 and PTEX150, components of the Plasmodium translocon of exported proteins (28), which were both robustly expressed (3 panels on the left), as well as the PVM protein PF10_0164 (14) and CSP (3 panels on the right). LSs at day 7 of infection were visualized with antibodies to EXP-2 (C), MSP1 (E), and in combination with MSP1 and EXP-1 (D). huHeps were visualized with antibody to human FAH in A, C, and E, and the liver sections were visualized by differential interference contrast microscopy (DIC) in C and D. DNA was visualized with DAPI in all panels. Note the nucleus of the infected hepatocyte in C, which has been pushed to the extremity of the infected hepatocyte (white arrow in the DNA panel). Scale bars: 10 μm (A, B, and D); 20 μm (C); 100 μm (E).