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Development of a model for marburgvirus based on severe-combined immunodeficiency mice.

Warfield KL, Alves DA, Bradfute SB, Reed DK, VanTongeren S, Kalina WV, Olinger GG, Bavari S - Virol. J. (2007)

Bottom Line: Here, we demonstrate that serially passaging liver homogenates from MARV-infected severe combined immunodeficient (scid) mice was highly successful in reducing the time to death in scid mice from 50-70 days to 7-10 days after MARV-Ci67, -Musoke, or -Ravn challenge.We performed serial sampling studies to characterize the pathology of these scid mouse-adapted MARV strains.These scid mouse-adapted MARV models appear to have many similar properties as the MARV models previously developed in guinea pigs and nonhuman primates.

View Article: PubMed Central - HTML - PubMed

Affiliation: United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA. kelly.warfield@us.army.mil

ABSTRACT
The filoviruses, Ebola (EBOV) and Marburg (MARV), cause a lethal hemorrhagic fever. Human isolates of MARV are not lethal to immmunocompetent adult mice and, to date, there are no reports of a mouse-adapted MARV model. Previously, a uniformly lethal EBOV-Zaire mouse-adapted virus was developed by performing 9 sequential passages in progressively older mice (suckling to adult). Evaluation of this model identified many similarities between infection in mice and nonhuman primates, including viral tropism for antigen-presenting cells, high viral titers in the spleen and liver, and an equivalent mean time to death. Existence of the EBOV mouse model has increased our understanding of host responses to filovirus infections and likely has accelerated the development of countermeasures, as it is one of the only hemorrhagic fever viruses that has multiple candidate vaccines and therapeutics. Here, we demonstrate that serially passaging liver homogenates from MARV-infected severe combined immunodeficient (scid) mice was highly successful in reducing the time to death in scid mice from 50-70 days to 7-10 days after MARV-Ci67, -Musoke, or -Ravn challenge. We performed serial sampling studies to characterize the pathology of these scid mouse-adapted MARV strains. These scid mouse-adapted MARV models appear to have many similar properties as the MARV models previously developed in guinea pigs and nonhuman primates. Also, as shown here, the scid-adapted MARV mouse models can be used to evaluate the efficacy of candidate antiviral therapeutic molecules, such as phosphorodiamidate morpholino oligomers or antibodies.

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Hematologic changes in mice infected with 'scid-adapted' MARV. Scid mice were infected with 1000 pfu of Ci67 P15, Musoke P10 or Ravn P10 'scid-adapted' MARV or left uninfected (naïve). Whole blood was collected from individual mice (n = 4–5/timepoint) in EDTA via terminal cardiac puncture at the indicated timepoints. (A) Total numbers white blood cells (WBC), (B) percentage of lymphocytes, (C) absolute numbers of lymphocytes, and (D) platelet counts in the blood were assessed and are presented as the mean value (± standard deviation).
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Figure 3: Hematologic changes in mice infected with 'scid-adapted' MARV. Scid mice were infected with 1000 pfu of Ci67 P15, Musoke P10 or Ravn P10 'scid-adapted' MARV or left uninfected (naïve). Whole blood was collected from individual mice (n = 4–5/timepoint) in EDTA via terminal cardiac puncture at the indicated timepoints. (A) Total numbers white blood cells (WBC), (B) percentage of lymphocytes, (C) absolute numbers of lymphocytes, and (D) platelet counts in the blood were assessed and are presented as the mean value (± standard deviation).

Mentions: As expected, there was a noticeable and steady weight loss in mice infected with the 'scid-adapted' MARV beginning around 4–5 days after infection (Figure 2A). Similar to what is seen in guinea pigs and monkeys, infection with the 'scid-adapted' MARV viruses caused detectable viremia within 2 days of infection (Figure 2B). The viremia in all the mice increased logarithmically over the course of the infection and peaked around 106 pfu/ml in the serum at days 6–8 (Figure 2B). Serum levels of blood urea nitrogen (BUN) and glucose dropped sharply over time after infection of the scid mice (Figure 2C–D). As is seen in all other models of filovirus infection, indicators of liver health such as alanine transaminase (ALT) and aspartate transaminase (AST) function increased as the MARV disease progressed (Figure 2E–F). As shown by the total number of circulating white blood cells (WBC), percentage of lymphocytes, and absolute numbers of lymphocytes within the blood of the 'scid-adapted' MARV-infected mice, the very low number of circulating WBC and lymphocytes remained fairly steady until very late in the disease (Figure 3A–C). Most of the cells in the lymphoid system of scid mice are NK cells, except for a few immature B or T cells due to 'leakiness' of the scid system, and this explains the low WBC and lymphocyte counts in Figure 3A–C. A steady decrease in the number of platelets in the blood after infection was observed of the scid mice with the 'scid-adapted' MARV (Figure 3D). As would be expected with a coagulopathic disease and similar to filovirus infections in nonhuman primates [20,22], we observed elevations in serum d-dimer levels by ELISA with values >500 ng/ml by 6–8 days post infection (data not shown).


Development of a model for marburgvirus based on severe-combined immunodeficiency mice.

Warfield KL, Alves DA, Bradfute SB, Reed DK, VanTongeren S, Kalina WV, Olinger GG, Bavari S - Virol. J. (2007)

Hematologic changes in mice infected with 'scid-adapted' MARV. Scid mice were infected with 1000 pfu of Ci67 P15, Musoke P10 or Ravn P10 'scid-adapted' MARV or left uninfected (naïve). Whole blood was collected from individual mice (n = 4–5/timepoint) in EDTA via terminal cardiac puncture at the indicated timepoints. (A) Total numbers white blood cells (WBC), (B) percentage of lymphocytes, (C) absolute numbers of lymphocytes, and (D) platelet counts in the blood were assessed and are presented as the mean value (± standard deviation).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2164958&req=5

Figure 3: Hematologic changes in mice infected with 'scid-adapted' MARV. Scid mice were infected with 1000 pfu of Ci67 P15, Musoke P10 or Ravn P10 'scid-adapted' MARV or left uninfected (naïve). Whole blood was collected from individual mice (n = 4–5/timepoint) in EDTA via terminal cardiac puncture at the indicated timepoints. (A) Total numbers white blood cells (WBC), (B) percentage of lymphocytes, (C) absolute numbers of lymphocytes, and (D) platelet counts in the blood were assessed and are presented as the mean value (± standard deviation).
Mentions: As expected, there was a noticeable and steady weight loss in mice infected with the 'scid-adapted' MARV beginning around 4–5 days after infection (Figure 2A). Similar to what is seen in guinea pigs and monkeys, infection with the 'scid-adapted' MARV viruses caused detectable viremia within 2 days of infection (Figure 2B). The viremia in all the mice increased logarithmically over the course of the infection and peaked around 106 pfu/ml in the serum at days 6–8 (Figure 2B). Serum levels of blood urea nitrogen (BUN) and glucose dropped sharply over time after infection of the scid mice (Figure 2C–D). As is seen in all other models of filovirus infection, indicators of liver health such as alanine transaminase (ALT) and aspartate transaminase (AST) function increased as the MARV disease progressed (Figure 2E–F). As shown by the total number of circulating white blood cells (WBC), percentage of lymphocytes, and absolute numbers of lymphocytes within the blood of the 'scid-adapted' MARV-infected mice, the very low number of circulating WBC and lymphocytes remained fairly steady until very late in the disease (Figure 3A–C). Most of the cells in the lymphoid system of scid mice are NK cells, except for a few immature B or T cells due to 'leakiness' of the scid system, and this explains the low WBC and lymphocyte counts in Figure 3A–C. A steady decrease in the number of platelets in the blood after infection was observed of the scid mice with the 'scid-adapted' MARV (Figure 3D). As would be expected with a coagulopathic disease and similar to filovirus infections in nonhuman primates [20,22], we observed elevations in serum d-dimer levels by ELISA with values >500 ng/ml by 6–8 days post infection (data not shown).

Bottom Line: Here, we demonstrate that serially passaging liver homogenates from MARV-infected severe combined immunodeficient (scid) mice was highly successful in reducing the time to death in scid mice from 50-70 days to 7-10 days after MARV-Ci67, -Musoke, or -Ravn challenge.We performed serial sampling studies to characterize the pathology of these scid mouse-adapted MARV strains.These scid mouse-adapted MARV models appear to have many similar properties as the MARV models previously developed in guinea pigs and nonhuman primates.

View Article: PubMed Central - HTML - PubMed

Affiliation: United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA. kelly.warfield@us.army.mil

ABSTRACT
The filoviruses, Ebola (EBOV) and Marburg (MARV), cause a lethal hemorrhagic fever. Human isolates of MARV are not lethal to immmunocompetent adult mice and, to date, there are no reports of a mouse-adapted MARV model. Previously, a uniformly lethal EBOV-Zaire mouse-adapted virus was developed by performing 9 sequential passages in progressively older mice (suckling to adult). Evaluation of this model identified many similarities between infection in mice and nonhuman primates, including viral tropism for antigen-presenting cells, high viral titers in the spleen and liver, and an equivalent mean time to death. Existence of the EBOV mouse model has increased our understanding of host responses to filovirus infections and likely has accelerated the development of countermeasures, as it is one of the only hemorrhagic fever viruses that has multiple candidate vaccines and therapeutics. Here, we demonstrate that serially passaging liver homogenates from MARV-infected severe combined immunodeficient (scid) mice was highly successful in reducing the time to death in scid mice from 50-70 days to 7-10 days after MARV-Ci67, -Musoke, or -Ravn challenge. We performed serial sampling studies to characterize the pathology of these scid mouse-adapted MARV strains. These scid mouse-adapted MARV models appear to have many similar properties as the MARV models previously developed in guinea pigs and nonhuman primates. Also, as shown here, the scid-adapted MARV mouse models can be used to evaluate the efficacy of candidate antiviral therapeutic molecules, such as phosphorodiamidate morpholino oligomers or antibodies.

Show MeSH
Related in: MedlinePlus