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Comparison of monkeypox viruses pathogenesis in mice by in vivo imaging.

Osorio JE, Iams KP, Meteyer CU, Rocke TE - PLoS ONE (2009)

Bottom Line: Intraperitoneal (IP) injection of both MPXV-Congo and MPXV-Congo/Luc+resulted in a systemic clinical disease and the same mean time-to-death at 9 (+/-0) days post-infection.Animals infected with the MPXV-USA/Luc+had less intense luminescence in tissues than those inoculated with MPXV-Congo/Luc+, and systemic spread of the MPXV-USA/Luc+virus occurred approximately two days later than the MPXV-Congo/Luc+.The ovary was an important target for viral replication as evidenced by the high viral titers and immunohistochemistry.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA. osorio@svm.vetmed.wisc.edu

ABSTRACT
Monkeypox viruses (MPXV) cause human monkeypox, a zoonotic smallpox-like disease endemic to Africa, and are of worldwide public health and biodefense concern. Using viruses from the Congo (MPXV-2003-Congo-358) and West African (MPXV-2003-USA-044) clades, we constructed recombinant viruses that express the luciferase gene (MPXV-Congo/Luc+and MPXV-USA-Luc+) and compared their viral infection in mice by biophotonic imaging. BALB/c mice became infected by both MPXV clades, but they recovered and cleared the infection within 10 days post-infection (PI). However, infection in severe combined immune deficient (SCID) BALB/c mice resulted in 100% lethality. Intraperitoneal (IP) injection of both MPXV-Congo and MPXV-Congo/Luc+resulted in a systemic clinical disease and the same mean time-to-death at 9 (+/-0) days post-infection. Likewise, IP injection of SCID-BALB/c mice with MPXV-USA or the MPXV-USA-Luc+, resulted in similar disease but longer (P<0.05) mean time-to-death (11+/-0 days) for both viruses compared to the Congo strains. Imaging studies in SCID mice showed luminescence in the abdomen within 24 hours PI with subsequent spread elsewhere. Animals infected with the MPXV-USA/Luc+had less intense luminescence in tissues than those inoculated with MPXV-Congo/Luc+, and systemic spread of the MPXV-USA/Luc+virus occurred approximately two days later than the MPXV-Congo/Luc+. The ovary was an important target for viral replication as evidenced by the high viral titers and immunohistochemistry. These studies demonstrate the suitability of a mouse model and biophotonic imaging to compare the disease progression and tissue tropism of MPX viruses.

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Virus titers from selected tissues and correlation with luminescence.Tissues samples from kidney, liver, lung and ovaries were aseptically harvested to compare viral titers between the parental MPXV-USA-2003 and recombinant progeny MPXV-USA-Luc+strains. Tissue homogenates were centrifuged as described in materials and methods section. Viral titers were calculated per gram of tissue.
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pone-0006592-g004: Virus titers from selected tissues and correlation with luminescence.Tissues samples from kidney, liver, lung and ovaries were aseptically harvested to compare viral titers between the parental MPXV-USA-2003 and recombinant progeny MPXV-USA-Luc+strains. Tissue homogenates were centrifuged as described in materials and methods section. Viral titers were calculated per gram of tissue.

Mentions: To monitor viral titers, tissues were aseptically harvested at the time of death to compare viral titers between the parental viruses and recombinant progeny Luc+strains and to correlate titers with luminescence levels. No differences in viral titer were detected for the Congo Luc+and wt strains for kidney (P = 0.49), liver (P = 0.22), lung (P = 0.25) and ovary (P = 0.60). Likewise, no differences in viral titer were detected between animals infected with the USA/Luc+and wt strains (Figure 4) for kidney (P = 0.41), liver (P = 0.75), lung (P = 0.68), and ovary (P = 0.89). These results provide further support that insertion of the luciferase gene did not substantially alter virulence of the virus. Viral titers in the ovaries were about 2 logs higher than in other tissues for both the Congo and USA strains. Using data collected from kidney, liver and lung extracts from both MPXV-Luc+strains, a correlation (Figure 5) was detected between measured luminescence and viral titer (R2 = 54%; P = 0.0008). Data from ovarian extracts were not included in the analysis because viral titers were much higher than the other tissues. With the resulting calibration curve generated, approximate viral titer can be calculated in future studies using the following formula: titer = 38.587+0.0011 photons/s/µl.


Comparison of monkeypox viruses pathogenesis in mice by in vivo imaging.

Osorio JE, Iams KP, Meteyer CU, Rocke TE - PLoS ONE (2009)

Virus titers from selected tissues and correlation with luminescence.Tissues samples from kidney, liver, lung and ovaries were aseptically harvested to compare viral titers between the parental MPXV-USA-2003 and recombinant progeny MPXV-USA-Luc+strains. Tissue homogenates were centrifuged as described in materials and methods section. Viral titers were calculated per gram of tissue.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2719101&req=5

pone-0006592-g004: Virus titers from selected tissues and correlation with luminescence.Tissues samples from kidney, liver, lung and ovaries were aseptically harvested to compare viral titers between the parental MPXV-USA-2003 and recombinant progeny MPXV-USA-Luc+strains. Tissue homogenates were centrifuged as described in materials and methods section. Viral titers were calculated per gram of tissue.
Mentions: To monitor viral titers, tissues were aseptically harvested at the time of death to compare viral titers between the parental viruses and recombinant progeny Luc+strains and to correlate titers with luminescence levels. No differences in viral titer were detected for the Congo Luc+and wt strains for kidney (P = 0.49), liver (P = 0.22), lung (P = 0.25) and ovary (P = 0.60). Likewise, no differences in viral titer were detected between animals infected with the USA/Luc+and wt strains (Figure 4) for kidney (P = 0.41), liver (P = 0.75), lung (P = 0.68), and ovary (P = 0.89). These results provide further support that insertion of the luciferase gene did not substantially alter virulence of the virus. Viral titers in the ovaries were about 2 logs higher than in other tissues for both the Congo and USA strains. Using data collected from kidney, liver and lung extracts from both MPXV-Luc+strains, a correlation (Figure 5) was detected between measured luminescence and viral titer (R2 = 54%; P = 0.0008). Data from ovarian extracts were not included in the analysis because viral titers were much higher than the other tissues. With the resulting calibration curve generated, approximate viral titer can be calculated in future studies using the following formula: titer = 38.587+0.0011 photons/s/µl.

Bottom Line: Intraperitoneal (IP) injection of both MPXV-Congo and MPXV-Congo/Luc+resulted in a systemic clinical disease and the same mean time-to-death at 9 (+/-0) days post-infection.Animals infected with the MPXV-USA/Luc+had less intense luminescence in tissues than those inoculated with MPXV-Congo/Luc+, and systemic spread of the MPXV-USA/Luc+virus occurred approximately two days later than the MPXV-Congo/Luc+.The ovary was an important target for viral replication as evidenced by the high viral titers and immunohistochemistry.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA. osorio@svm.vetmed.wisc.edu

ABSTRACT
Monkeypox viruses (MPXV) cause human monkeypox, a zoonotic smallpox-like disease endemic to Africa, and are of worldwide public health and biodefense concern. Using viruses from the Congo (MPXV-2003-Congo-358) and West African (MPXV-2003-USA-044) clades, we constructed recombinant viruses that express the luciferase gene (MPXV-Congo/Luc+and MPXV-USA-Luc+) and compared their viral infection in mice by biophotonic imaging. BALB/c mice became infected by both MPXV clades, but they recovered and cleared the infection within 10 days post-infection (PI). However, infection in severe combined immune deficient (SCID) BALB/c mice resulted in 100% lethality. Intraperitoneal (IP) injection of both MPXV-Congo and MPXV-Congo/Luc+resulted in a systemic clinical disease and the same mean time-to-death at 9 (+/-0) days post-infection. Likewise, IP injection of SCID-BALB/c mice with MPXV-USA or the MPXV-USA-Luc+, resulted in similar disease but longer (P<0.05) mean time-to-death (11+/-0 days) for both viruses compared to the Congo strains. Imaging studies in SCID mice showed luminescence in the abdomen within 24 hours PI with subsequent spread elsewhere. Animals infected with the MPXV-USA/Luc+had less intense luminescence in tissues than those inoculated with MPXV-Congo/Luc+, and systemic spread of the MPXV-USA/Luc+virus occurred approximately two days later than the MPXV-Congo/Luc+. The ovary was an important target for viral replication as evidenced by the high viral titers and immunohistochemistry. These studies demonstrate the suitability of a mouse model and biophotonic imaging to compare the disease progression and tissue tropism of MPX viruses.

Show MeSH
Related in: MedlinePlus