Limits...
Humanized HLA-DR4.RagKO.IL2RγcKO.NOD (DRAG) mice sustain the complex vertebrate life cycle of Plasmodium falciparum malaria.

Wijayalath W, Majji S, Villasante EF, Brumeanu TD, Richie TL, Casares S - Malar. J. (2014)

Bottom Line: Malaria is a deadly infectious disease affecting millions of people in tropical and sub-tropical countries.Among the five species of Plasmodium parasites that infect humans, Plasmodium falciparum accounts for the highest morbidity and mortality associated with malaria.Four week-old DRAG mice were infused with HLA-matched human haematopoietic stem cells (HSC) and examined for reconstitution of human liver cells and erythrocytes.

View Article: PubMed Central - PubMed

Affiliation: US Military Malaria Vaccine Program, Naval Medical Research Center/Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA. sofia.a.casares.civ@mail.mil.

ABSTRACT

Background: Malaria is a deadly infectious disease affecting millions of people in tropical and sub-tropical countries. Among the five species of Plasmodium parasites that infect humans, Plasmodium falciparum accounts for the highest morbidity and mortality associated with malaria. Since humans are the only natural hosts for P. falciparum, the lack of convenient animal models has hindered the understanding of disease pathogenesis and prompted the need of testing anti-malarial drugs and vaccines directly in human trials. Humanized mice hosting human cells represent new pre-clinical models for infectious diseases that affect only humans. In this study, the ability of human-immune-system humanized HLA-DR4.RagKO.IL2RγcKO.NOD (DRAG) mice to sustain infection with P. falciparum was explored.

Methods: Four week-old DRAG mice were infused with HLA-matched human haematopoietic stem cells (HSC) and examined for reconstitution of human liver cells and erythrocytes. Upon challenge with infectious P. falciparum sporozoites (NF54 strain) humanized DRAG mice were examined for liver stage infection, blood stage infection, and transmission to Anopheles stephensi mosquitoes.

Results: Humanized DRAG mice reconstituted human hepatocytes, Kupffer cells, liver endothelial cells, and erythrocytes. Upon intravenous challenge with P. falciparum sporozoites, DRAG mice sustained liver to blood stage infection (average 3-5 parasites/microlitre blood) and allowed transmission to An. stephensi mosquitoes. Infected DRAG mice elicited antibody and cellular responses to the blood stage parasites and self-cured the infection by day 45 post-challenge.

Conclusions: DRAG mice represent the first human-immune-system humanized mouse model that sustains the complex vertebrate life cycle of P. falciparum without the need of exogenous injection of human hepatocytes/erythrocytes or P. falciparum parasite adaptation. The ability of DRAG mice to elicit specific human immune responses to P. falciparum parasites may help deciphering immune correlates of protection and to identify protective malaria antigens.

Show MeSH

Related in: MedlinePlus

DRAG mice sustain the complete vertebrate life cycle ofP. falciparuminfection. A) HSC-infused DRAG mice were challenged i.v. with 105 infectious P. falciparum sporozoites and five days later the livers were stained with anti-PfHSP70 (green) and DAPI (DNA, blue) and analysed by confocal microscopy. Data show a representative P. falciparum liver stage schizont. Scale bars are 10 μm. B) DRAG mice were challenged with sporozoites as above and followed for blood stage parasitaemia by PCR using primers specific for Plasmodium 18S rRNA. Data show percentage of parasitaemic mice (n = 31) from five independent challenges. C) PCR analysis in a group of four HSC-infused DRAG mice at day 28 post-challenge. NC, negative control; PC, positive control; M, DNA molecular markers. D) Giemsa staining of thick (upper panel) and thin (lower panel) blood smears from infected DRAG mice. Arrows show the presence of P. falciparum rings in thick smears and trophozoites in thin smears.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4197321&req=5

Fig4: DRAG mice sustain the complete vertebrate life cycle ofP. falciparuminfection. A) HSC-infused DRAG mice were challenged i.v. with 105 infectious P. falciparum sporozoites and five days later the livers were stained with anti-PfHSP70 (green) and DAPI (DNA, blue) and analysed by confocal microscopy. Data show a representative P. falciparum liver stage schizont. Scale bars are 10 μm. B) DRAG mice were challenged with sporozoites as above and followed for blood stage parasitaemia by PCR using primers specific for Plasmodium 18S rRNA. Data show percentage of parasitaemic mice (n = 31) from five independent challenges. C) PCR analysis in a group of four HSC-infused DRAG mice at day 28 post-challenge. NC, negative control; PC, positive control; M, DNA molecular markers. D) Giemsa staining of thick (upper panel) and thin (lower panel) blood smears from infected DRAG mice. Arrows show the presence of P. falciparum rings in thick smears and trophozoites in thin smears.

Mentions: Since DRAG mice develop human hepatocytes, Kupffer cells, endothelial cells, and erythrocytes, it was next investigated whether they sustain the vertebrate life cycle of P. falciparum. For this, DRAG mice were challenged i.v. with P. falciparum sporozoites (NF54, 105 per mouse) and five days later the livers were examined by immunohistochemistry using anti-P. falciparum HSP70 (PfHSP70). Plasmodium falciparum liver stage schizonts were detected in the livers (Figure 4A), which demonstrated that human hepatocytes developed by DRAG mice sustain infection by P. falciparum sporozoites.Figure 4


Humanized HLA-DR4.RagKO.IL2RγcKO.NOD (DRAG) mice sustain the complex vertebrate life cycle of Plasmodium falciparum malaria.

Wijayalath W, Majji S, Villasante EF, Brumeanu TD, Richie TL, Casares S - Malar. J. (2014)

DRAG mice sustain the complete vertebrate life cycle ofP. falciparuminfection. A) HSC-infused DRAG mice were challenged i.v. with 105 infectious P. falciparum sporozoites and five days later the livers were stained with anti-PfHSP70 (green) and DAPI (DNA, blue) and analysed by confocal microscopy. Data show a representative P. falciparum liver stage schizont. Scale bars are 10 μm. B) DRAG mice were challenged with sporozoites as above and followed for blood stage parasitaemia by PCR using primers specific for Plasmodium 18S rRNA. Data show percentage of parasitaemic mice (n = 31) from five independent challenges. C) PCR analysis in a group of four HSC-infused DRAG mice at day 28 post-challenge. NC, negative control; PC, positive control; M, DNA molecular markers. D) Giemsa staining of thick (upper panel) and thin (lower panel) blood smears from infected DRAG mice. Arrows show the presence of P. falciparum rings in thick smears and trophozoites in thin smears.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4197321&req=5

Fig4: DRAG mice sustain the complete vertebrate life cycle ofP. falciparuminfection. A) HSC-infused DRAG mice were challenged i.v. with 105 infectious P. falciparum sporozoites and five days later the livers were stained with anti-PfHSP70 (green) and DAPI (DNA, blue) and analysed by confocal microscopy. Data show a representative P. falciparum liver stage schizont. Scale bars are 10 μm. B) DRAG mice were challenged with sporozoites as above and followed for blood stage parasitaemia by PCR using primers specific for Plasmodium 18S rRNA. Data show percentage of parasitaemic mice (n = 31) from five independent challenges. C) PCR analysis in a group of four HSC-infused DRAG mice at day 28 post-challenge. NC, negative control; PC, positive control; M, DNA molecular markers. D) Giemsa staining of thick (upper panel) and thin (lower panel) blood smears from infected DRAG mice. Arrows show the presence of P. falciparum rings in thick smears and trophozoites in thin smears.
Mentions: Since DRAG mice develop human hepatocytes, Kupffer cells, endothelial cells, and erythrocytes, it was next investigated whether they sustain the vertebrate life cycle of P. falciparum. For this, DRAG mice were challenged i.v. with P. falciparum sporozoites (NF54, 105 per mouse) and five days later the livers were examined by immunohistochemistry using anti-P. falciparum HSP70 (PfHSP70). Plasmodium falciparum liver stage schizonts were detected in the livers (Figure 4A), which demonstrated that human hepatocytes developed by DRAG mice sustain infection by P. falciparum sporozoites.Figure 4

Bottom Line: Malaria is a deadly infectious disease affecting millions of people in tropical and sub-tropical countries.Among the five species of Plasmodium parasites that infect humans, Plasmodium falciparum accounts for the highest morbidity and mortality associated with malaria.Four week-old DRAG mice were infused with HLA-matched human haematopoietic stem cells (HSC) and examined for reconstitution of human liver cells and erythrocytes.

View Article: PubMed Central - PubMed

Affiliation: US Military Malaria Vaccine Program, Naval Medical Research Center/Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA. sofia.a.casares.civ@mail.mil.

ABSTRACT

Background: Malaria is a deadly infectious disease affecting millions of people in tropical and sub-tropical countries. Among the five species of Plasmodium parasites that infect humans, Plasmodium falciparum accounts for the highest morbidity and mortality associated with malaria. Since humans are the only natural hosts for P. falciparum, the lack of convenient animal models has hindered the understanding of disease pathogenesis and prompted the need of testing anti-malarial drugs and vaccines directly in human trials. Humanized mice hosting human cells represent new pre-clinical models for infectious diseases that affect only humans. In this study, the ability of human-immune-system humanized HLA-DR4.RagKO.IL2RγcKO.NOD (DRAG) mice to sustain infection with P. falciparum was explored.

Methods: Four week-old DRAG mice were infused with HLA-matched human haematopoietic stem cells (HSC) and examined for reconstitution of human liver cells and erythrocytes. Upon challenge with infectious P. falciparum sporozoites (NF54 strain) humanized DRAG mice were examined for liver stage infection, blood stage infection, and transmission to Anopheles stephensi mosquitoes.

Results: Humanized DRAG mice reconstituted human hepatocytes, Kupffer cells, liver endothelial cells, and erythrocytes. Upon intravenous challenge with P. falciparum sporozoites, DRAG mice sustained liver to blood stage infection (average 3-5 parasites/microlitre blood) and allowed transmission to An. stephensi mosquitoes. Infected DRAG mice elicited antibody and cellular responses to the blood stage parasites and self-cured the infection by day 45 post-challenge.

Conclusions: DRAG mice represent the first human-immune-system humanized mouse model that sustains the complex vertebrate life cycle of P. falciparum without the need of exogenous injection of human hepatocytes/erythrocytes or P. falciparum parasite adaptation. The ability of DRAG mice to elicit specific human immune responses to P. falciparum parasites may help deciphering immune correlates of protection and to identify protective malaria antigens.

Show MeSH
Related in: MedlinePlus