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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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Histological changes in spleens of mice infected with 'scid-adapted' MARV. Scid mice were challenged IP with 1000 pfu of 'scid-adapted' MARV-Ci67 and tissue samples were collected on days 0, 2, 4, 6, and 8 after challenge (n = 4–5/group). (A-G) Tissues from the MARV-infected mice were stained with hematoxylin and eosin and representative pictures from day 0 (A-B), 4 (C-D), and 6 (E-G) are shown. (A-B) Control scid mouse sampled at day 0 (i.e. uninfected) contain abnormal spleen morphology due to lack of B and T lymphocytes. (C-F) Spleens from the MARV-infected scid mice at days 4 and 6 display increasingly more visual loss of cells in both the red and white pulp. (G) At late stages of the disease, the spleen contains notable necrosis/apoptosis of lymphocytes often with tingible body macrophages and large lymphoblasts in the white pulp. (H) Immunoperoxidase stain of a spleen from a scid mouse at 6 days postinfection showing presence of Marburg viral antigen (brown). Magnifications were 4× for panels A, C, and E, 20× for panels B, D, and F, and 40× for panels G-H.
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Figure 6: Histological changes in spleens of mice infected with 'scid-adapted' MARV. Scid mice were challenged IP with 1000 pfu of 'scid-adapted' MARV-Ci67 and tissue samples were collected on days 0, 2, 4, 6, and 8 after challenge (n = 4–5/group). (A-G) Tissues from the MARV-infected mice were stained with hematoxylin and eosin and representative pictures from day 0 (A-B), 4 (C-D), and 6 (E-G) are shown. (A-B) Control scid mouse sampled at day 0 (i.e. uninfected) contain abnormal spleen morphology due to lack of B and T lymphocytes. (C-F) Spleens from the MARV-infected scid mice at days 4 and 6 display increasingly more visual loss of cells in both the red and white pulp. (G) At late stages of the disease, the spleen contains notable necrosis/apoptosis of lymphocytes often with tingible body macrophages and large lymphoblasts in the white pulp. (H) Immunoperoxidase stain of a spleen from a scid mouse at 6 days postinfection showing presence of Marburg viral antigen (brown). Magnifications were 4× for panels A, C, and E, 20× for panels B, D, and F, and 40× for panels G-H.

Mentions: As compared to the spleens of uninfected mice (Figures 6A–B), there was multifocal lymphocyte depletion and lymphocytolysis in the periarteriolar lymphoid sheaths (PALS) and follicles of the MARV-infected scid mice (Figures 6C–F). These changes were minimal to mild at 4 days postinfection, but more severe by day 6 postinfection. Much of this lymphocyte damage appeared due to apoptosis of cells within the red and white pulp based on TUNEL staining of tissues (Figure 7). We observed increased numbers of apoptotic-like bodies labeled by TUNEL as early as days 2 and 4 postinfection, with greater numbers of TUNEL-positive bodies at days 6 and 8 postinfection. In mice killed at 6 or 8 days postinfection, the spleens of infected mice contained large, lymphoblastic cells within splenic marginal zones (Figure 6G). Consistent with previous studies in other filovirus animal models [14-16], the majority of the MARV-infected cells within the spleen were located within the red pulp and appeared to be phagocytic cells such as macrophages and dendritic cells (Figure 6H).


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)

Histological changes in spleens of mice infected with 'scid-adapted' MARV. Scid mice were challenged IP with 1000 pfu of 'scid-adapted' MARV-Ci67 and tissue samples were collected on days 0, 2, 4, 6, and 8 after challenge (n = 4–5/group). (A-G) Tissues from the MARV-infected mice were stained with hematoxylin and eosin and representative pictures from day 0 (A-B), 4 (C-D), and 6 (E-G) are shown. (A-B) Control scid mouse sampled at day 0 (i.e. uninfected) contain abnormal spleen morphology due to lack of B and T lymphocytes. (C-F) Spleens from the MARV-infected scid mice at days 4 and 6 display increasingly more visual loss of cells in both the red and white pulp. (G) At late stages of the disease, the spleen contains notable necrosis/apoptosis of lymphocytes often with tingible body macrophages and large lymphoblasts in the white pulp. (H) Immunoperoxidase stain of a spleen from a scid mouse at 6 days postinfection showing presence of Marburg viral antigen (brown). Magnifications were 4× for panels A, C, and E, 20× for panels B, D, and F, and 40× for panels G-H.
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getmorefigures.php?uid=PMC2164958&req=5

Figure 6: Histological changes in spleens of mice infected with 'scid-adapted' MARV. Scid mice were challenged IP with 1000 pfu of 'scid-adapted' MARV-Ci67 and tissue samples were collected on days 0, 2, 4, 6, and 8 after challenge (n = 4–5/group). (A-G) Tissues from the MARV-infected mice were stained with hematoxylin and eosin and representative pictures from day 0 (A-B), 4 (C-D), and 6 (E-G) are shown. (A-B) Control scid mouse sampled at day 0 (i.e. uninfected) contain abnormal spleen morphology due to lack of B and T lymphocytes. (C-F) Spleens from the MARV-infected scid mice at days 4 and 6 display increasingly more visual loss of cells in both the red and white pulp. (G) At late stages of the disease, the spleen contains notable necrosis/apoptosis of lymphocytes often with tingible body macrophages and large lymphoblasts in the white pulp. (H) Immunoperoxidase stain of a spleen from a scid mouse at 6 days postinfection showing presence of Marburg viral antigen (brown). Magnifications were 4× for panels A, C, and E, 20× for panels B, D, and F, and 40× for panels G-H.
Mentions: As compared to the spleens of uninfected mice (Figures 6A–B), there was multifocal lymphocyte depletion and lymphocytolysis in the periarteriolar lymphoid sheaths (PALS) and follicles of the MARV-infected scid mice (Figures 6C–F). These changes were minimal to mild at 4 days postinfection, but more severe by day 6 postinfection. Much of this lymphocyte damage appeared due to apoptosis of cells within the red and white pulp based on TUNEL staining of tissues (Figure 7). We observed increased numbers of apoptotic-like bodies labeled by TUNEL as early as days 2 and 4 postinfection, with greater numbers of TUNEL-positive bodies at days 6 and 8 postinfection. In mice killed at 6 or 8 days postinfection, the spleens of infected mice contained large, lymphoblastic cells within splenic marginal zones (Figure 6G). Consistent with previous studies in other filovirus animal models [14-16], the majority of the MARV-infected cells within the spleen were located within the red pulp and appeared to be phagocytic cells such as macrophages and dendritic cells (Figure 6H).

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