Respiratory infection of mice with mammalian reoviruses causes systemic infection with age and strain dependent pneumonia and encephalitis
© Gauvin et al.; licensee BioMed Central Ltd. 2013
Received: 27 July 2012
Accepted: 25 February 2013
Published: 1 March 2013
Because mammalian reoviruses are isolated from the respiratory tract we modeled the natural history of respiratory infection of adult and suckling mice with T1 Lang (T1L) and T3 Dearing (T3D) reoviruses.
Adult and suckling Balb/c mice were infected by the intranasal route and were assessed for dose response of disease as well as viral replication in the lung and other organs. Viral antigen was assessed by immunofluorescence and HRP staining of tissue sections and histopathology was assessed on formalin fixed, H + E stained tissue sections.
Intranasal infection of adult mice resulted in fatal respiratory distress for high doses (107 pfu) of T1L but not T3D. In contrast both T1L and T3D killed suckling mice at moderate viral dosages (105 pfu) but differed in clinical symptoms where T1L induced respiratory failure and T3D caused encephalitis. Infections caused transient viremia that resulted in spread to peripheral tissues where disease correlated with virus replication, and pathology. Immunofluorescent staining of viral antigens in the lung showed reovirus infection was primarily associated with alveoli with lesser involvement of bronchiolar epithelium. Immunofluorescent and HRP staining of viral antigens in brain showed infection of neurons by T3D and glial cells by T1L.
These mouse models of reovirus respiratory infection demonstrated age and strain dependent disease that are expected to be relevant to understanding and modulating natural and therapeutic reovirus infections in humans.
KeywordsMammalian reovirus Pathogenesis Pneumonia Systemic infection Intranasal infection Serotype 3 Dearing Serotype 1 Lang Encephalitis Immunofluorescence Liver Lung Suckling mouse Viremia
Reovirus serotype 3 Dearing
Reovirus serotype 1 Lang
Plaque forming units
Median lethal dose
Horse radish peroxidase.
Although mammalian orthoreovirus infection is not associated with disease, viruses are isolated from the respiratory and enteric tracts of humans and animals [1–4]. Natural infection with reoviruses may therefore involve either the nasal and/or oral routes of transmission. Recently serotype 3 strain Dearing (T3D) has been shown to possess oncolytic properties and is currently in clinical trials in humans raising fundamental questions regarding the natural history and normal patterns of reovirus infection in humans [5–7] as well as animal models.
Depending on the reovirus strain the suckling mouse can be infected by injection to cause encephalitis [8, 9] and myocarditis [10–12], and the oral route of infection has been shown to differ in effectiveness among reoviruses. In particular type1 strain Lang (T1L) and murine type 3 isolate Clone 9, can establish infection in suckling mice but not adult mice via the oral route [13–15], and high dosages of type 3 strain Dearing (T3D) are required for infection of mice via the oral route in both suckling and adult animals [16, 17].
Although the prototype T1L and T3D viruses were initially isolated from stool samples of human infants, clinical specimens of reoviruses are routinely isolated from human respiratory tracts . However, experimental data regarding mammalian reovirus respiratory infections are limited. Intranasal infection of adult volunteers has been demonstrated for all 3 serotypes of reoviruses (T1L, T2 Jones, and T3D) indicating that humans are infectable by the respiratory route using high dosages (107 pfu) of virus with the induction of relatively mild clinical signs of respiratory infection for some patients . The respiratory route, has been less well studied in the mouse, however models of T1L induced respiratory disease are described in specific strains of mice where CBA/J mice induced acute respiratory distress (ARD) which has been studied primarily from the standpoint of the immune responses to infection [18–20] but has also been shown to cause systemic spread via the blood to the spleen and intestine . Pneumonia is also induced by T1L in other strains of mice (CD-1, Balb-c, and C3H) but with less severe pathology . Although respiratory infection of mice with strains other than the prototype T1L reovirus has not been described, reovirus respiratory infection has been studied for T1L and T3D in adult rats which resulted in fatal pneumonia for T1L infections [23, 24]. Recently lung infection of CBA/J mice via the intranasal route with T1L has been shown to be enhanced by prior uncoating with protease treatment .
Given that nasal infection of suckling mice has not been described for reoviruses we assessed the response of adult and suckling Balb-c mice to intranasal infection with T1L and T3D reoviruses. We found that both reoviruses establish infections in adult and suckling mice with high level replication in the lung as well as spread to involve peripheral organs. Fatal disease was associated with high dosage of T1L but not T3D in adult mice and with moderate dosages of T1L and T3D in suckling mice. The pattern of symptoms, viral replication and histopathology were consistent with fatal T1L pneumonia and T3D encephalitis. These data define the basic virological and pathological response to respiratory infection with reoviruses, indicating that both T1L and T3D can readily establish infection by the respiratory route but that these viral types differ in their tropism. T1L and T3D were pneumotropic but differed in extent. T3D also demonstrated fatal neurotropic infection following respiratory infection of new-born but not adult animals. Viral spread appeared to occur via the blood stream for both T1L and T3D viruses.
Viruses and cells
T1L and T3D prototype strains and L929 cells were originally obtained from Dr. B.N. Fields laboratory. Viruses were propagated and titrated in mouse L 929 cells grown in MEM plus 5% fetal bovine serum and penicillin and streptomycin as described previously .
Mouse infections and titrations
Adult female 4–6 week old Balb-c mice (Charles River, St. Hyacinthe, Quebec) were anaesthetized with halothane (3% in oxygen) before infection by application of virus suspended in 0.05 ml PBS onto the nose pad. This method introduces virus into the lung as evident by distribution of trypan blue dye into lung tissues of anaesthetized mice that were euthanized without recovery from anaesthetization (data not shown). Suckling Balb-c mice were similarly infected at 2 days of age with 0.01 ml volumes of virus. Survival was monitored for 30 days. Viral growth and pathology were determined on tissues collected from mice euthanized by CO2 narcosis. Blood was collected by cardiac puncture. Organs from duplicate animals were collected at each time point, suspended in 9 volumes of PBS and disrupted by sonication for 4 minutes on ice using a microprobe and the Model F60 Fisher Scientific sonicator at power setting 5–7 before duplicate titrations by plaque assay in L929 cells to yield 2 technical replicate titrations for each experimental replicate. Infectious titres were calculated per gram of tissue. Data was plotted as mean values with variation shown as ± 1 standard error.
Animal ethics approval
This study was carried out in accordance and compliance with the guidelines of the Canadian Council on Animal Care (CCAC) as outlined in the Care and Use of Experimental Animals, Vol.1, 2nd Edn. (1993), which are recognized as “best-practices” by the International Council for Laboratory Animal Science (ICLAS). The protocol was approved by the University of Ottawa Animal Care Committee (Protocol Number: BMI-85).
Adult mice were perfused with PBS and then formalin (3.75% formaldehyde in PBS) before dissection and removal of organs for immersion in formalin for 24 hr, paraffin embedding, sectioning and hematoxylin and eosin staining. Suckling mice were not perfused before fixation but instead were dissected and placed in formalin for 24 hr fixation with the exception of lungs that were inflated with formalin under 25 cm water pressure for 15 minutes before further fixation and processing as described for adult tissues. Horse radish peroxide (HRP) staining of formalin fixed paraffin embedded T1L and T3D infected brain tissues was done as described previously . Images were collected using the 10X objective using an Olympus BX50 microscope.
Frozen sectioning and immunofluorescent staining
Animals were sacrificed and perfused as described above before excising tissues that were snap frozen on dry ice in OCT compound (Fisher Scientific, Ottawa) for sectioning as previously described . Tissue sections were fixed with cold acetone before immunofluorescent staining using the corresponding rabbit immune serum produced against purified T1L or T3D viruses. Immune sera were preadsorbed with acetone extracted, powdered mouse tissues (10% (w/v) tissue mixed with serum for 16 hr at 4 C). Primary antibodies were diluted (1/800) in 0.3% BSA in PBS and incubated with sections for 0.5 hr followed by 3 × 5 min washes in PBS. The secondary antibody was CY3 conjugated donkey anti rabbit IgG (1/800 dilution) (Jackson Labs, Maine) that was reacted as for the primary antibodies. After the last PBS wash the sections were incubated with DAPI (1 ug/ml) for 2 minutes to stain nuclei. Images were collected using an epifluorescent Leica DMXRA 2 microscope (Leica Mississauga ON) using a Hamamatsu ORCA ER camera (Hamamatsu Corp., Bridgewater, NJ) running OpenLab v3.17 software (Improvision, Lexington, MA). Images were subsequently processed using Adobe Photoshop (Adobe Systems, San Jose CA).
Statistical analysis employed the single sample or paired t test as indicated, using the Microsoft Office 2007 XL program.
As the suckling mouse model of mammalian reovirus infection has been extensively studied following inoculation via the oral and injection routes, we set out to extend this analysis to the comparison of infection in adults and suckling mice following respiratory inoculation. Intranasal instillation of virus inoculum into anaesthetized mice results in the introduction of virus into the upper respiratory tract and lung.
Age and virus dependent pneumonia and encephalitis in response to intranasal infection
In contrast to adult mice, both T1L and T3D viruses resulted in lethal infections in suckling mice with similar dose responses (LD50 of 105 pfu), however the time to death and the clinical symptoms of infection were significantly different (t test, p = 0.0082) (Figure 1). Suckling mice infected with T1L developed respiratory crackling sounds on day 1 or 2 that progressed to severe respiratory distress and death by day 7. Suckling mice infected with T3D also manifested respiratory crackling on day 2 but this resolved by day 8 and was followed by signs of neurological dysfunction and death commencing on day 11. Neurological symptoms included tremors with darting and/or agitated behavior, spinning or turning, ataxia, and asymmetric gait. These experiments showed that respiratory infection with T1L and T3D not only induced different types of diseases in suckling mice but also differed in their ability to induce disease in adult mice.
Viral replication in the lung and spread to peripheral organs
The yield of infectious virus was also measured for suckling mice infected via the respiratory route with the same dose of virus as employed for adult mice (105 pfu). In the lung and liver, reovirus T1L grew to significantly higher levels than T3D, p = 0.0064 and 0.0009, for days 4–8 and 2–8 respectively (by paired t test, n = 6–8) (Figure 3). In the brain T1L and T3D produced similar levels of virus until day 6 where after T3D grew to produce 1000 fold more virus on day 8 pi. Virus yield comparisons were not determined beyond day 8 because T1L produced lethal responses by day 7 pi. The high T3D titre in the brain was consistent with neurological signs of encephalitis in T3D infected suckling mice. The higher yield of T1L relative to T3D in suckling mouse lungs was also consistent with increased respiratory damage observed as respiratory distress. Both T1L and T3D grew to higher titres in the suckling mouse relative to the adult animal (Figure 3) which was consistent with their greater virulence in suckling animals.
Immunofluorescent staining of mouse lungs demonstrated infection of alveoli
Immunofluorescent staining of brain
Similar to the brain data, the livers of adult mice were negative by immunofluoresent staining at day 7 pi for T1L and T3D antigen (data not shown). Staining of uninfected mouse organs with anti-reovirus serum revealed no signal, as expected (data not shown). In contrast, staining of reovirus antigen at the same time point was seen in liver sections of suckling mice although this involved only a small number of hepatocytes that were more easily detectable in T1L infected than T3D infected livers (data not shown). Therefore the ability to detect antigen-positive cells in suckling brain and liver relative to adults was correlated with greater replication of mammalian reoviruses in suckling tissues than adult organs.
Infection of the liver of adult mice was associated with some minor foci of necrosis and inflammatory cells primarily associated with the vasculature and biliary ducts (data not shown). This pattern was more extensive in suckling mice, where T1L infection was associated with detectable areas of necrotic lesions and inflammatory cells, as indicated with arrows in panels h and j of Figure 9, relative to control sections shown in Figure 9g.
Histopathological assessments of adult and suckling mice following intranasal infection
T1L virus infection
T3D virus infection
severe patchy pneumonia, alveolar debris, lymphocytic infiltration, distended bronchioles and alveoli
mild to moderate pneumonia, discrete lymphocytic infiltration
few necrotic foci with cell degeneration and polymorphonuclearleukocytes
edema, necrotic foci (fewer than T1L)
numerous white follicles
numerous white follicles
appears normal with some lymphocytes
severe pneumonia as seen for the adult infection
minor areas of lymphocytes
encephalitis, dark staining condensed cells
necrotic foci and lymphocytes
less numerous necrotic foci and lymphocytes
In this paper we extend the mouse models of reovirus infection to the respiratory tract where we demonstrate that both adult and suckling mice are readily infected via intranasal inoculation with prototype T1L and T3D reoviruses. Intranasal inoculation resulted in extensive lung infection that became systemic within the first day of infection. The pattern of disease was both type and age specific where T1L caused fatal, acute respiratory distress and T3D did not. In contrast, T3D produced an age-dependant fatal encephalitis in newborn but not adult mice. This indicated a uniform ability of both serotypes to initiate infection via the respiratory route but the resulting infections induced strain dependent polymorphisms with respect to extent of tissue involvement and disease type.
The adult mouse model of respiratory reovirus infection
The overall adult mouse lung model of respiratory infection was characterized by local replication in alveolar epithelium coincident with appearance of virus in the blood stream. Within the first day of infection, blood borne virus infected peripheral organs to produce lower levels of infectious virus that were not associated with disease states. T1L was more pneumotropic than T3D and caused dose dependent fatal acute respiratory distress which occurred 4 days subsequent to the time of peak virus yield in the lung and thus appeared to be largely due to an immune mediated inflammatory response (as shown for T1L in the CBA/J mouse ). T3D does not replicate as well as T1L in the mouse lung (Figure 3) consistent with the findings of others in the rat lung .
The suckling mouse model of respiratory reovirus infection
The suckling mouse lung model of respiratory infection was similar to the adult model for T1L but differed for T3D. Although both types replicate in the lung, T1L was more pneumovirulent than T3D causing pneumonia in both suckling and adult mice. T3D produces clinical signs of respiratory infection that were not fatal but instead resulted in dose dependent fatal encephalitis that occurred on day 12, subsequent to maximal virus replication (>109 pfu/gram of brain) around day 8. The occurrence of disease subsequent to maximal virus yield again suggests a post-infectious host response to the virus as the cause of disease. Minor tissue necrosis was seen in the T1L infected liver and less so in T3D infection, which is consistent with the observation that the liver is the only site of tissue damage in the adult SCID model of intraperitoneal reovirus infection which is associated with systemic infection and hepatitis .
Reovirus grows to high titre in lungs
With respect to organ tropism, both T1L and T3D strains infected the lung and all peripheral tissues examined, but T1L replicated to higher levels in the lung that was associated with its greater ability to cause acute respiratory distress in the mouse; these findings parallel those found by others in rats . The clinical involvement of T1L infection with the lung was supported by the high level of infectious virus and infected lung tissue as well as the presence of interstitial alveolar inflammation. Both reovirus types grew to higher levels per gram of tissue in the suckling mouse lung that was associated with increased pneumovirulence of T1L but not T3D. Similar to adults, fatally infected T1L infected suckling mice demonstrated a time to death of 7 to 8 days, however these infections differed in dose response where fatal disease occurred with at a 100 fold reduced dose (105 versus 107 pfu). In contrast, suckling mice infected with similar doses of T3D lived beyond this time to subsequently die of neurologic disease.
Lung infection primarily involved alveolar tissues
Cellular tropism in the lung was largely restricted to alveolar tissue seen as dispersed foci of infected cells similar to the infection of type I alveolar pneumocytes described for infected rat lungs . Very little evidence of infection was seen for bronchiolar epithelium which was primarily detectable at later times, coincident with peak replication. The observation of alveolar rather than bronchiolar infection is opposite to the pattern seen for mouse infection with unadapted human viruses that produce local infections of the lung, i.e. influenza [28, 30, 31] and parainfluenza viruses [32, 33]. Previous analysis of infection of mouse enteric epithelium indicate entrance of virus through the apical side of M cells  followed by infection of the basolateral epithelial surfaces that contain 2 known reovirus receptors, sialic acid and junction adhesion molecule . Entry into the rat lung has also been shown to involve transport through M cells . Proteases present in mouse lung tissue may also promote infection by generating partially uncoated virions that can enter though M cells  where virus could subsequently disseminate to alveolar and peripheral organ sites for productive infection, possibly via infected endothelial cells in blood capillaries as was seen in infected brain (Figure 8b). Determination of the mechanistic details of infection and spread via the respiratory route in mice requires further analysis.
Respiratory reovirus infection resulted in systemic spread via the blood
Spread of virus in the suckling mouse has previously been shown to involve blood [4, 36] as well as neurons, with T3D employing primarily the neuronal route and T1L the hematogenous route . Our data are consistent with entrance of virus into the blood from the lung followed by systemic spread. The spread of virus to the liver in the first day of infection (Figure 3) must be via a fast route such as blood circulation since T3D virus can only travel 14 mm per day through nerves [37, 38]. Transmission of virus via nerves may however also be operating in the respiratory suckling mouse model as T3D virus was not detected in brain until day 2 suggesting a slower mode of spread to this site of infection, possibly from the nasal cavity via the olfactory nervous system. There may also be differences in infection and/or transport of T1L versus T3D through blood vessels because T1L has been shown to have an increased ability to replicate in endothelial cells . Previous analysis of intracranial injection of suckling mice showed that T1L infection was limited to ependymal cells surrounding the choroids plexus that induced fatal obstructive hydrocephalus [36, 40], however we observed T1L antigen positive cells in the brain parenchyma within structures suggestive of glia (Figure 8b). This was in marked contrast to T3D that caused neuronal infection and encephalitis that was consistent with oral and intracranial infection previously reported for suckling mice [8, 41]. Future studies are needed to determine the sequence of events involved in the entry and spread of reovirus from the mouse respiratory tract to peripheral tissues.
The ability of T3D to preferentially replicate in RAS transformed 3T3 cells has identified reovirus as an oncolytic virus [6, 7] that has now been demonstrated to replicate in a variety of tumor types as well as treat tumors in vivo models [5, 42–44]. Treatment of tumors with oncolytic viruses is a process of applied pathogenesis where viral infection is directed at tumor destruction rather than disease production. It is therefore necessary to know the pathogenesis of reovirus infection for all tissue types as a consequence of infection by various routes. A thorough understanding of reovirus infection via the respiratory route is thus of practical importance in defining the ability of reovirus to infect human tissues and cause disease or conversely for the application of reovirus to the treatment of cancer. The mouse model of respiratory infection is the only normal adult model of reovirus infection causing disease and thus extends earlier studies of pathogenesis in the infant mouse to the adult. As reovirus disease is generally more severe in the suckling mouse, the adult mouse respiratory infection may more closely represent normal human infections. Although many normal cells are resistant to infection we describe virus type and host age dependency in cellular susceptibility to reovirus infection. Indeed the increased replication of reovirus strains in suckling mice and the age dependence of encephalitis are both consistent with the preferential replication in tumors that are poorly differentiated and rapidly growing cell types. Furthermore infection with T3D did not produce disease in immunocompetent adult animals which supports its safe use as a therapeutic virus in humans.
This work was funded by the Natural Sciences and Engineering Research Council of Canada to EGB.
- Jackson GG, Muldoon RL: Viruses causing common respiratory infection in man. IV. Reoviruses and Adenoviruses. J Infect Dis 1973, 128:811–866.PubMedView Article
- Rosen L, Hovis JF, Mastrota FM, Bell JA, Huebner RJ: Observations on a newly recognized virus (Abney) of the reovirus family. Am J Hyg 1960, 71:258–265.PubMed
- Rosen L, Evans HE, Spickard A: Reovirus infections in human volunteers. Am J Hyg 1963, 77:29–37.PubMed
- Tyler KL: Fields' virology. 4th edition. Philadelphia: Lippincott Williams & Wilkins; 2001.
- Norman KL, Lee PW: Reovirus as a novel oncolytic agent. J Clin Invest 2000, 105:1035–1038.PubMedView Article
- Coffey MC, Strong JE, Forsyth PA, Lee PW: Reovirus therapy of tumors with activated Ras pathway. Science 1998, 282:1332–1334.PubMedView Article
- Strong JE, Coffey MC, Tang D, Sabinin P, Lee PW: The molecular basis of viral oncolysis: usurpation of the Ras signaling pathway by reovirus. EMBO J 1998, 17:3351–3362.PubMedView Article
- Raine CS, Fields BN: Reovirus type 3 encephalitis–a virologic and ultrastructural study. J Neuropathol Exp Neurol 1973, 32:19–33.PubMedView Article
- Margolis G, Kilham L, Gonatas NK: Reovirus type 3 encephalitis: observations of virus-cell interactions in neural tissues. I. Light microscopy studies. Lab Invest 1971, 24:91–100.PubMed
- Terheggen F, Benedikz E, Frissen PH, Brinkman K: Myocarditis associated with reovirus infection. Eur J Clin Microbiol Infect Dis 2003, 22:197–198.PubMed
- Sherry B: Pathogenesis of reovirus myocarditis. Curr Top Microbiol Immunol 1998, 233:51–66.PubMedView Article
- Sherry B, Schoen FJ, Wenske E, Fields BN: Derivation and characterization of an efficiently myocarditic reovirus variant. J Virol 1989, 63:4840–4849.PubMed
- Kauffman RS, Wolf JL, Finberg R, Trier JS, Fields BN: The sigma 1 protein determines the extent of spread of reovirus from the gastrointestinal tract of mice. Virology 1983, 124:403–410.PubMedView Article
- Derrien M, Fields BN: Anti-interleukin-3 and anti-nerve growth factor increase neonatal mice survival to reovirus type 3 clone 9 per oral challenge. J Neuroimmunol 2000, 110:209–213.PubMedView Article
- Derrien M, Fields BN: Reovirus type 3 clone 9 increases interleukin-1alpha level in the brain of neonatal, but not adult, mice. Virology 1999, 257:35–44.PubMedView Article
- Bodkin DK, Fields BN: Growth and survival of reovirus in intestinal tissue: role of the L2 and S1 genes. J Virol 1989, 63:1188–1193.PubMed
- Organ EL, Rubin DH: Pathogenesis of reovirus gastrointestinal and hepatobiliary disease. Curr Top Microbiol Immunol 1998, 233:67–83.PubMedView Article
- Majeski EI, Paintlia MK, Lopez AD, Harley RA, London SD, London L: Respiratory reovirus 1/L induction of intraluminal fibrosis, a model of bronchiolitis obliterans organizing pneumonia, is dependent on T lymphocytes. Am J Pathol 2003, 163:1467–1479.PubMedView Article
- Majeski EI, Harley RA, Bellum SC, London SD, London L: Differential role for T cells in the development of fibrotic lesions associated with reovirus 1/L-induced bronchiolitis obliterans organizing pneumonia versus acute respiratory distress syndrome. Am J Respir Cell Mol Biol 2003, 28:208–217.PubMedView Article
- Bellum SC, Dove D, Harley RA, Greene WB, Judson MA, London L: Respiratory reovirus 1/L induction of intraluminal fibrosis. A model for the study of bronchiolitis obliterans organizing pneumonia. Am J Pathol 1997, 150:2243–2254.PubMed
- London L, Majeski EI, Paintlia MK, Harley RA, London SD: Respiratory reovirus 1/L induction of diffuse alveolar damage: a model of acute respiratory distress syndrome. Exp Mol Pathol 2002, 72:24–36.PubMedView Article
- London L, Majeski EI, Altman-Hamamdzic S, Enockson C, Paintlia MK, Harley RA: Respiratory reovirus 1/L induction of diffuse alveolar damage: pulmonary fibrosis is not modulated by corticosteroids in acute respiratory distress syndrome in mice. Clin Immunol 2002, 103:284–295.PubMedView Article
- Morin MJ, Warner A, Fields BN: Reovirus infection in rat lungs as a model to study the pathogenesis of viral pneumonia. J Virol 1996, 70:541–548.PubMed
- Morin MJ, Warner A, Fields BN: A pathway for entry of retroviruses into the host through M cells of the respiratory tract. J Exp Med 1994, 180:1523–1527.PubMedView Article
- Nygaard RM, Golden JW, Schiff LA: Impact of host proteases on reovirus infection in the respiratory tract. J Virol 2012, 86:1238–1243.PubMedView Article
- Zou S, Brown EG: Stable expression of the reovirus mu2 protein in mouse L cells complements the growth of a reovirus ts mutant with a defect in its M1 gene. Virology 1996, 217:42–48.PubMedView Article
- Schlossmacher MG, Shimura H: Parkinson's disease: assays for the ubiquitin ligase activity of neural Parkin. Methods Mol Biol 2005, 301:351–369.PubMed
- Smeenk CA, Wright KE, Burns BF, Thaker AJ, Brown EG: Mutations in the hemagglutinin and matrix genes of a virulent influenza virus variant, A/FM/1/47-MA, control different stages in pathogenesis. Virus Res 1996, 44:79–95.PubMedView Article
- Haller BL, Barkon ML, Vogler GP, Virgin HW: Genetic mapping of reovirus virulence and organ tropism in severe combined immunodeficient mice: organ-specific virulence genes. J Virol 1995, 69:357–364.PubMed
- Sweet C, Smith H: Pathogenicity of influenza virus. Microbiol Rev 1980, 44:303–330.PubMed
- Smith H, Sweet C: Lessons for human influenza from pathogenicity studies with ferrets. Rev Infect Dis 1988, 10:56–75.PubMedView Article
- Kuiken T, van den Hoogen BG, van Riel DA, Laman JD, van Amerongen G, Sprong L: Experimental human metapneumovirus infection of cynomolgus macaques (Macaca fascicularis) results in virus replication in ciliated epithelial cells and pneumocytes with associated lesions throughout the respiratory tract. Am J Pathol 2004, 164:1893–1900.PubMedView Article
- Machii K, Otsuka Y, Iwai H, Ueda K: Infection of rabbits with Sendai virus. Lab Anim Sci 1989, 39:334–337.PubMed
- Wolf JL, Rubin DH, Finberg R, Kauffman RS, Sharpe AH, Trier JS: Intestinal M cells: a pathway for entry of reovirus into the host. Science 1981, 212:471–472.PubMedView Article
- Helander A, Silvey KJ, Mantis NJ, Hutchings AB, Chandran K, Lucas WT: The viral sigma1 protein and glycoconjugates containing alpha2–3-linked sialic acid are involved in type 1 reovirus adherence to M cell apical surfaces. J Virol 2003, 77:7964–7977.PubMedView Article
- Kilham L, Margolis G: Hydrocephalus in hamsters, ferrets, rats, and mice following inoculations with reovirus type I. I. Virologic studies. Lab Invest 1969, 21:183–188.PubMed
- Tyler KL, McPhee DA, Fields BN: Distinct pathways of viral spread in the host determined by reovirus S1 gene segment. Science 1986, 233:770–774.PubMedView Article
- Tyler KL, Virgin HW, Bassel-Duby R, Fields BN: Antibody inhibits defined stages in the pathogenesis of reovirus serotype 3 infection of the central nervous system. J Exp Med 1989, 170:887–900.PubMedView Article
- Matoba Y, Colucci WS, Fields BN, Smith TW: The reovirus M1 gene determines the relative capacity of growth of reovirus in cultured bovine aortic endothelial cells. J Clin Invest 1993, 92:2883–2888.PubMedView Article
- Margolis G, Kilham L: Hydrocephalus in hamsters, ferrets, rats, and mice following inoculations with reovirus type I. II. Pathologic studies. Lab Invest 1969, 21:189–198.PubMed
- Tyler KL, Bronson RT, Byers KB, Fields B: Molecular basis of viral neurotropism: experimental reovirus infection. Neurology 1985, 35:88–92.PubMedView Article
- Hirasawa K, Nishikawa SG, Norman KL, Alain T, Kossakowska A, Lee PW: Oncolytic reovirus against ovarian and colon cancer. Cancer Res 2002, 62:1696–1701.PubMed
- Norman KL, Coffey MC, Hirasawa K, Demetrick DJ, Nishikawa SG, DiFrancesco LM: Reovirus oncolysis of human breast cancer. Hum Gene Ther 2002, 13:641–652.PubMedView Article
- Wilcox ME, Yang W, Senger D, Rewcastle NB, Morris DG, Brasher PM: Reovirus as an oncolytic agent against experimental human malignant gliomas. J Natl Cancer Inst 2001, 93:903–912.PubMedView Article
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