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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.

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Plasmodium falciparumblood stage parasites from infected DRAG mice expand inin vitrocultures. A) Giemsa staining of in vitro cultures showing presence of rings (r), trophozoites (t) and schizonts (s) (left and middle panels) and gametocytes (right panel). B)Anopheles stephensi mosquitoes were fed on the gametocyte cultures (four independent membrane feedings) or directly on an infected DRAG mouse (day 28 post-challenge). Oocysts in midgut and sporozoites in salivary glands were examined at days 7 and 14 post-feeding, respectively. Data represent frequency of infected mosquitoes among 25–35 mosquitoes analysed individually. C) Oocysts in midgut of mosquitoes fed on an infected DRAG mouse.
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Fig5: Plasmodium falciparumblood stage parasites from infected DRAG mice expand inin vitrocultures. A) Giemsa staining of in vitro cultures showing presence of rings (r), trophozoites (t) and schizonts (s) (left and middle panels) and gametocytes (right panel). B)Anopheles stephensi mosquitoes were fed on the gametocyte cultures (four independent membrane feedings) or directly on an infected DRAG mouse (day 28 post-challenge). Oocysts in midgut and sporozoites in salivary glands were examined at days 7 and 14 post-feeding, respectively. Data represent frequency of infected mosquitoes among 25–35 mosquitoes analysed individually. C) Oocysts in midgut of mosquitoes fed on an infected DRAG mouse.

Mentions: Plasmodium falciparum blood stage parasites from the peripheral blood of infected DRAG mice expanded upon in vitro culture. Figure 5A (left and middle panels) shows the presence of P. falciparum rings (r), trophozoites (t), and schizonts (s) in the in vitro cultures. The asexual blood stage parasites differentiated into gametocytes (g) (Figure 5A, right panel), and developed into oocysts and sporozoites in An. stephensi mosquitoes fed on the gametocyte cultures (Figure 5B). Anopheles stephensi mosquitoes directly fed on infected DRAG mice (day 28 post-challenge) also developed oocysts and sporozoites (Figure 5B and C). In aggregate these results indicated that DRAG mice sustain the complex vertebrate life cycle of P. falciparum.Figure 5


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)

Plasmodium falciparumblood stage parasites from infected DRAG mice expand inin vitrocultures. A) Giemsa staining of in vitro cultures showing presence of rings (r), trophozoites (t) and schizonts (s) (left and middle panels) and gametocytes (right panel). B)Anopheles stephensi mosquitoes were fed on the gametocyte cultures (four independent membrane feedings) or directly on an infected DRAG mouse (day 28 post-challenge). Oocysts in midgut and sporozoites in salivary glands were examined at days 7 and 14 post-feeding, respectively. Data represent frequency of infected mosquitoes among 25–35 mosquitoes analysed individually. C) Oocysts in midgut of mosquitoes fed on an infected DRAG mouse.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig5: Plasmodium falciparumblood stage parasites from infected DRAG mice expand inin vitrocultures. A) Giemsa staining of in vitro cultures showing presence of rings (r), trophozoites (t) and schizonts (s) (left and middle panels) and gametocytes (right panel). B)Anopheles stephensi mosquitoes were fed on the gametocyte cultures (four independent membrane feedings) or directly on an infected DRAG mouse (day 28 post-challenge). Oocysts in midgut and sporozoites in salivary glands were examined at days 7 and 14 post-feeding, respectively. Data represent frequency of infected mosquitoes among 25–35 mosquitoes analysed individually. C) Oocysts in midgut of mosquitoes fed on an infected DRAG mouse.
Mentions: Plasmodium falciparum blood stage parasites from the peripheral blood of infected DRAG mice expanded upon in vitro culture. Figure 5A (left and middle panels) shows the presence of P. falciparum rings (r), trophozoites (t), and schizonts (s) in the in vitro cultures. The asexual blood stage parasites differentiated into gametocytes (g) (Figure 5A, right panel), and developed into oocysts and sporozoites in An. stephensi mosquitoes fed on the gametocyte cultures (Figure 5B). Anopheles stephensi mosquitoes directly fed on infected DRAG mice (day 28 post-challenge) also developed oocysts and sporozoites (Figure 5B and C). In aggregate these results indicated that DRAG mice sustain the complex vertebrate life cycle of P. falciparum.Figure 5

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