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Analysis of innate defences against Plasmodium falciparum in immunodeficient mice.

Arnold L, Tyagi RK, Mejia P, Van Rooijen N, Pérignon JL, Druilhe P - Malar. J. (2010)

Bottom Line: The systematic and kinetic analysis of the remaining innate immune responses included the number and phenotype of peripheral blood leukocytes as well as inflammatory cytokines/chemokines released in periphery.The innate responses towards the murine parasite Plasmodium yoelii were used as a control.Those results bring new insights on the ability of innate immunity from immunodeficient mice to control xenografts of cells of human origin and human pathogens.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Parasitologie Bio-Médicale, Institut Pasteur, 28, rue du Dr Roux, 75015 Paris, France.

ABSTRACT

Background: Mice with genetic deficiencies in adaptive immunity are used for the grafting of human cells or pathogens, to study human diseases, however, the innate immune responses to xenografts in these mice has received little attention. Using the NOD/SCID Plasmodium falciparum mouse model an analysis of innate defences responsible for the substantial control of P. falciparum which remains in such mice, was performed.

Methods: NOD/SCID mice undergoing an immunomodulatory protocol that includes, clodronate-loaded liposomes to deplete macrophages and an anti-polymorphonuclear leukocytes antibody, were grafted with human red blood cells and P. falciparum. The systematic and kinetic analysis of the remaining innate immune responses included the number and phenotype of peripheral blood leukocytes as well as inflammatory cytokines/chemokines released in periphery. The innate responses towards the murine parasite Plasmodium yoelii were used as a control.

Results: Results show that 1) P. falciparum induces a strong inflammation characterized by an increase in circulating leukocytes and the release of inflammatory cytokines; 2) in contrast, the rodent parasite P. yoelii, induces a far more moderate inflammation; 3) human red blood cells and the anti-inflammatory agents employed induce low-grade inflammation; and 4) macrophages seem to bear the most critical function in controlling P. falciparum survival in those mice, whereas polymorphonuclear and NK cells have only a minor role.

Conclusions: Despite the use of an immunomodulatory treatment, immunodeficient NOD/SCID mice are still able to mount substantial innate responses that seem to be correlated with parasite clearance. Those results bring new insights on the ability of innate immunity from immunodeficient mice to control xenografts of cells of human origin and human pathogens.

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Patterns of blood parasitaemia observed in NOD/SCID mice. In four independent experiments, a total of 84 NOD/SCID mice were infected with a single i.p. infection of P. falciparum 3D7 strain on day 0 and HuRBC (500 μl of pellet at 50% haematocrit), clo-lip (200 μl) and NIMP-R14 (10 mg/kg) antibody were injected i.p. every 3 days as previously described (black arrows). The preparatory phase prior to the injection of infected HuRBC is not shown. Parasitaemia was measured on tail blood smears by counting the number of infected RBC among 10000 total human and mouse RBC. Parasitemia lower than 0,001 are not considered. The figure shows the average parasitaemia ± SD, and the percentages (and number of mice) corresponding to each pattern of parasitemia.
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Figure 1: Patterns of blood parasitaemia observed in NOD/SCID mice. In four independent experiments, a total of 84 NOD/SCID mice were infected with a single i.p. infection of P. falciparum 3D7 strain on day 0 and HuRBC (500 μl of pellet at 50% haematocrit), clo-lip (200 μl) and NIMP-R14 (10 mg/kg) antibody were injected i.p. every 3 days as previously described (black arrows). The preparatory phase prior to the injection of infected HuRBC is not shown. Parasitaemia was measured on tail blood smears by counting the number of infected RBC among 10000 total human and mouse RBC. Parasitemia lower than 0,001 are not considered. The figure shows the average parasitaemia ± SD, and the percentages (and number of mice) corresponding to each pattern of parasitemia.

Mentions: Although stable long-lasting parasitaemia could be obtained and employed for various applications [8,11] the pattern of parasitaemia has never been homogeneous, i.e. varied greatly from one animal to the other, and the various attempts to modify the protocol failed to improve results significantly. For instance, among a total of 84 mice studied recently under rigorous and well-controlled conditions using the standard immunomodulation protocol described above, four different patterns of peripheral blood parasitaemia could be described (summarized in Figure 1). Following a single infection by P. falciparum, 17% of mice remained parasitologically negative, 34% showed a transient parasitaemia lasting for ca. 12 days post-infection, 12% showed a stable parasitaemia for more than 20 days and 37% showed an almost total parasite clearance from peripheral blood, however followed by a re-emergence a few days later, without new parasite inoculation, i.e. a second wave of parasitaemia lasting for the life-span of the animal. The sequence of events of the latter pattern considered the most informative, was selected for further analysis.


Analysis of innate defences against Plasmodium falciparum in immunodeficient mice.

Arnold L, Tyagi RK, Mejia P, Van Rooijen N, Pérignon JL, Druilhe P - Malar. J. (2010)

Patterns of blood parasitaemia observed in NOD/SCID mice. In four independent experiments, a total of 84 NOD/SCID mice were infected with a single i.p. infection of P. falciparum 3D7 strain on day 0 and HuRBC (500 μl of pellet at 50% haematocrit), clo-lip (200 μl) and NIMP-R14 (10 mg/kg) antibody were injected i.p. every 3 days as previously described (black arrows). The preparatory phase prior to the injection of infected HuRBC is not shown. Parasitaemia was measured on tail blood smears by counting the number of infected RBC among 10000 total human and mouse RBC. Parasitemia lower than 0,001 are not considered. The figure shows the average parasitaemia ± SD, and the percentages (and number of mice) corresponding to each pattern of parasitemia.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2914061&req=5

Figure 1: Patterns of blood parasitaemia observed in NOD/SCID mice. In four independent experiments, a total of 84 NOD/SCID mice were infected with a single i.p. infection of P. falciparum 3D7 strain on day 0 and HuRBC (500 μl of pellet at 50% haematocrit), clo-lip (200 μl) and NIMP-R14 (10 mg/kg) antibody were injected i.p. every 3 days as previously described (black arrows). The preparatory phase prior to the injection of infected HuRBC is not shown. Parasitaemia was measured on tail blood smears by counting the number of infected RBC among 10000 total human and mouse RBC. Parasitemia lower than 0,001 are not considered. The figure shows the average parasitaemia ± SD, and the percentages (and number of mice) corresponding to each pattern of parasitemia.
Mentions: Although stable long-lasting parasitaemia could be obtained and employed for various applications [8,11] the pattern of parasitaemia has never been homogeneous, i.e. varied greatly from one animal to the other, and the various attempts to modify the protocol failed to improve results significantly. For instance, among a total of 84 mice studied recently under rigorous and well-controlled conditions using the standard immunomodulation protocol described above, four different patterns of peripheral blood parasitaemia could be described (summarized in Figure 1). Following a single infection by P. falciparum, 17% of mice remained parasitologically negative, 34% showed a transient parasitaemia lasting for ca. 12 days post-infection, 12% showed a stable parasitaemia for more than 20 days and 37% showed an almost total parasite clearance from peripheral blood, however followed by a re-emergence a few days later, without new parasite inoculation, i.e. a second wave of parasitaemia lasting for the life-span of the animal. The sequence of events of the latter pattern considered the most informative, was selected for further analysis.

Bottom Line: The systematic and kinetic analysis of the remaining innate immune responses included the number and phenotype of peripheral blood leukocytes as well as inflammatory cytokines/chemokines released in periphery.The innate responses towards the murine parasite Plasmodium yoelii were used as a control.Those results bring new insights on the ability of innate immunity from immunodeficient mice to control xenografts of cells of human origin and human pathogens.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de Parasitologie Bio-Médicale, Institut Pasteur, 28, rue du Dr Roux, 75015 Paris, France.

ABSTRACT

Background: Mice with genetic deficiencies in adaptive immunity are used for the grafting of human cells or pathogens, to study human diseases, however, the innate immune responses to xenografts in these mice has received little attention. Using the NOD/SCID Plasmodium falciparum mouse model an analysis of innate defences responsible for the substantial control of P. falciparum which remains in such mice, was performed.

Methods: NOD/SCID mice undergoing an immunomodulatory protocol that includes, clodronate-loaded liposomes to deplete macrophages and an anti-polymorphonuclear leukocytes antibody, were grafted with human red blood cells and P. falciparum. The systematic and kinetic analysis of the remaining innate immune responses included the number and phenotype of peripheral blood leukocytes as well as inflammatory cytokines/chemokines released in periphery. The innate responses towards the murine parasite Plasmodium yoelii were used as a control.

Results: Results show that 1) P. falciparum induces a strong inflammation characterized by an increase in circulating leukocytes and the release of inflammatory cytokines; 2) in contrast, the rodent parasite P. yoelii, induces a far more moderate inflammation; 3) human red blood cells and the anti-inflammatory agents employed induce low-grade inflammation; and 4) macrophages seem to bear the most critical function in controlling P. falciparum survival in those mice, whereas polymorphonuclear and NK cells have only a minor role.

Conclusions: Despite the use of an immunomodulatory treatment, immunodeficient NOD/SCID mice are still able to mount substantial innate responses that seem to be correlated with parasite clearance. Those results bring new insights on the ability of innate immunity from immunodeficient mice to control xenografts of cells of human origin and human pathogens.

Show MeSH
Related in: MedlinePlus