RESUMEN
Filoviruses, including Ebola virus (EBOV) and Marburg virus (MARV), cause severe hemorrhagic fever in humans and nonhuman primates with high mortality rates. There is no approved therapy against these deadly viruses. Antiviral drug development has been hampered by the requirement of a biosafety level (BSL)-4 facility to handle infectious EBOV and MARV because of their high pathogenicity to humans. In this study, we aimed to establish a surrogate animal model that can be used for anti-EBOV and -MARV drug screening under BSL-2 conditions by focusing on the replication-competent recombinant vesicular stomatitis virus (rVSV) pseudotyped with the envelope glycoprotein (GP) of EBOV (rVSV/EBOV) and MARV (rVSV/MARV), which has been investigated as vaccine candidates and thus widely used in BSL-2 laboratories. We first inoculated mice, rats, and hamsters intraperitoneally with rVSV/EBOV and found that only hamsters showed disease signs and succumbed within 4 days post-infection. Infection with rVSV/MARV also caused lethal infection in hamsters. Both rVSV/EBOV and rVSV/MARV were detected at high titers in multiple organs including the liver, spleen, kidney, and lungs of infected hamsters, indicating acute and systemic infection resulting in fatal outcomes. Therapeutic effects of passive immunization with an anti-EBOV neutralizing antibody were specifically observed in rVSV/EBOV-infected hamsters. Thus, this animal model is expected to be a useful tool to facilitate in vivo screening of anti-filovirus drugs targeting the GP molecule.
Asunto(s)
Modelos Animales de Enfermedad , Ebolavirus/genética , Marburgvirus/genética , Estomatitis Vesicular/virología , Vesiculovirus/genética , Proteínas del Envoltorio Viral/genética , Animales , Anticuerpos Antivirales/administración & dosificación , Cricetinae , Susceptibilidad a Enfermedades , Evaluación Preclínica de Medicamentos , Ebolavirus/inmunología , Mesocricetus , Ratones , Ratas , Vacunas Sintéticas , Estomatitis Vesicular/patología , Estomatitis Vesicular/prevención & control , Estomatitis Vesicular/terapia , Vesiculovirus/patogenicidad , Proteínas del Envoltorio Viral/inmunología , Carga ViralRESUMEN
Three 80- to 95-month-old Holstein dairy cattle infected naturally with the agent of bovine spongiform encephalopathy (BSE) and slaughtered at abattoirs in Japan were examined for the distribution of disease-specific and protease-resistant prion protein (PrP(Sc)) by immunohistochemistry (IHC) and Western blot (WB) analyses. The cattle showed no clinical signs or symptoms relevant to BSE but were screened as positive by enzyme-linked immunosorbent assay, a rapid test for BSE. This positive result was confirmed by IHC or WB in a specimen of the medulla oblongata. Histopathologically, these cattle showed no vacuolation in tissue sections from the central nervous system except for the medulla oblongata. Both IHC and WB analyses revealed PrP(Sc) accumulation in the brain, spinal cord, satellite and ganglionic cells of the dorsal root ganglia, and the myenteric plexus of the distal ileum. In addition, small amounts of PrP(Sc) were detected in the peripheral nerves of 2 cattle by WB. No PrP(Sc) was demonstrated by either method in the Peyer's patches of the distal ileum; lymphoid tissues including the palatine tonsils, lymph nodes, and spleen; or other tissues. The distribution of PrP(Sc) accumulation in the preclinical stage was different between naturally infected cattle and cattle inoculated experimentally with the BSE agent.