Isolation of novel bovine parainfluenza virus type 5 (bPIV5) and its incidence in Korean cattle / 대한수의학회지

Four viruses showing cytopathic effects in MDBK cells were isolated from brains of cattle showing downer cattle syndrome in 2012. The isolates were confirmed to belong to the genus Rubulavirus of the subfamily Paramyxovirinae. Isolate QIA-B1201 had the ability to hemagglutinate red blood cells from several species of animals and was capable of adsorbing guinea pig erythrocytes on the surface of infected Vero cells. Nucleotide sequence analysis showed that two isolates (QIA-B1201 and QIA-B1204) had high similarity with other human and animal PIV5 isolates ranging from 98.1 to 99.8%. The highest sequence similarity of the two isolates corresponded to strain KNU-11 (99.8% at the nucleotide and amino acid level) isolated from suckling piglets in Korea in 2012. To evaluate the virulence of strain QIA-B1201, we inoculated bPIV5 into 5 week-old mice via both the intraperitoneal and intracranial route. Body weight was not significantly altered in mice inoculated with QIA-B1201. In this study, we isolated and characterized novel bPIV5s from brain samples showing downer cattle syndrome, but were not able to elucidate the pathogenicity of the bPIV5s in mice.

Transcription of interferon stimulated genes in response to porcine rubulavirus infection in vitro

Porcine rubulavirus (PoRV) is an emerging virus causing meningo-encephalitis and reproductive failures in pigs. Little is known about the pathogenesis and immune evasion of this virus; therefore research on the mechanisms underlying tissue damage during infection is essential. To explore these mechanisms, the effect of PoRV on the transcription of interferon (IFN) pathway members was analyzed in vitro by semi-quantitative RT-PCR. Ten TCID50 of PoRV stimulated transcription of IFNá, IFNâ, STAT1, STAT2, p48 and OAS genes in neuroblastoma cells, whereas infection with 100 TCID50 did not stimulate transcription levels more than non-infected cells. When the cells were primed with IFNá, infection with 1 TCDI50 of PoRV sufficed to stimulate the transcription of the same genes, but 10 and 100 TCID50 did not modify the transcription level of those genes as compared with non-infected and primed controls. MxA gene transcription was observed only when the cells were primed with IFNá and stimulated with 10 TCID50, whereas 100 TCID50 of PoRV did not modify the MxA transcription level as compared to non-infected and primed cells. Our results show that PoRV replication at low titers stimulates the expression of IFN-responsive genes in neuroblastoma cells, and suggest that replication of PoRV at higher titers inhibits the transcription of several members of the IFN pathway. These findings may contribute to the understanding of the pathogenesis of PoRV.

Caracterización biológica de tres aislamientos naturales del Rubulavirus porcino (México)

Biological characterization of three natural isolates of the porcine rubulavirus (Mexico). Porcine rubulavirus (PoRV) produces a neurological and reproductive syndrome in pigs called the blue-eye disease, known only from Mexico. Several isolates were grouped by the main symptoms presented during outbreaks: a) neurotropic in piglets, b) broadly neurotropic in piglets and gonadotropic in adults, and c) gonadotropic in adults. We studied some biological properties of three strains, which fall in one of each virus group: La Piedad Michoacán (LPM) and Producción Animal Cerdos 1 (PAC1) and 3 (PAC3), respectively. The analyzed viral properties are mainly related with the trans-membrane hemagglutinin-neuraminidase (HN) and fusion (F) proteins, such as cytopathic effect, hemolysis, hemagglutinating (HA) and neuraminidase (NA) activities. In the infection assays PAC1 strain presented the highest fusogenicity level; however, the most cytolytic strain was PAC3. In addition, HA and NA activities and viral genome of PAC3 strain was detected in supernatants during cell infection earlier than in the other two strains, which shows that PAC3 virions release from the host cell earlier than LPM and PAC1. Experimental determination in purified viruses shows that PAC3 presented a higher HA and NA activities; however, PAC1 shows other interesting properties, such as a high thermostability of HN and differences about substrate profile respect to LPM and PAC3. Our data suggest that NA activity is associated with the virulence of RVP. Rev. Biol. Trop. 56 (2): 487-499. Epub 2008 June 30.

El Rubulavirus porcino causa un síndrome neurológico y reproductivo en cerdos, hasta ahora reportado sólo en México. Los virus aislados se agrupan de acuerdo con los síntomas principales observados durante los brotes en: a) neutrópicos en lechones, b) neurotrópicos en lechones/gonadotrópicos en adultos y c) gonadotrópicos en adultos. En este trabajo se estudiaron tres cepas: La Piedad Michoacán (LPM) y Producción Animal "Cerdos" 1 (PAC1) y 3 (PAC3), ubicadas respectivamente en cada grupo. Las propiedades estudiadas se relacionan principalmente con dos proteínas de la envoltura viral, la hemaglutinina-neuraminidasa (HN) y la proteína de fusión (F). Se cuantificaron el efecto citopático y las actividades de hemólisis, hemaglutinación (HA) y neuraminidasa (NA). En cultivo celular la cepa PAC1 presentó una mayor actividad fusogénica, sin embargo PAC3 presentó la mayor actividad citolítica. La cepa PAC3 fue la primera en ser detectada en sobrenadante de células infectadas (HA, NA y genoma), lo que muestra que sus viriones son liberados al medio antes que las otras dos cepas. PAC3 tuvo las actividades más altas de HA y NA, sin embargo, PAC1 presentó una mayor termoestabilidad en estas actividades de HN y un perfil de substrato algo distinto de los observados para LPM y PAC3. Estos datos sugieren que la actividad de NA está relacionada con la virulencia del RVP.

Effects of Mumps Virus Nucleocapsid Protein on the Viral Replication and Apoptosis in VeroE6 Cells

Apoptosis, as a part of the natural defense mechanisms that protect against viral infection, plays a vital role in the pathogenic mechanisms. It also plays a key role in the pathogenesis of diseases including many viral diseases. Mechanisms of virus-induced apoptosis are not completely understood because of the complexity of the underlying biochemical cascades and all of the participating host factors. Mumps virus belongs to the genus Rubulavirus in the family Paramyxoviridae. It contains single stranded RNA genome with negative polarity. It was observed that mumps virus induced apoptosis in VeroE6 cells, and adsorption and penetration of mumps virus to cell membrane alone were not sufficient for the induction of cell death. When mumps virus was superinfected onto nucleocapsid protein (NP) expressing VeroE6 cells, cell viability and facterial titer were maintained until 13 and 12 day, respectively. The levels of p53, Bax, and Bcl-2 were increased in NP-expressing VeroE6 cells, and the increase in Bax, and Bcl-2 was outstanding. It was observed that NP protein did not directly affect the efficiency of the infection of mumps virus in NP-expressing VeroE6 cells. The levels of p53, and Bax were decreased in both mock-infected VeroE6 cells and NP-expressing VeroE6 cells infected with mumps virus. However, the Bcl-2 level was little affected by the virus infection.

Production and Characterization of Monoclonal Antibodies to Mumps Virus Isolated in Korea

Classical mumps patients develop bilateral or less commonly unilateral parotitis. Mumps virus belongs to the genus Rubulavirus in the family Paramyxoviridae. It contains single stranded RNA genome with negative polarity. To characterize the antigenicity of mumps virus isolated in Korea, nineteen hybridoma cell lines producing monoclonal antibodies to mumps virus were established by fusion of Sp2/0-Ag14 mouse myeloma cells with spleen cells of mice immunized with mumps virus strain 98-40. The specificity of these monoclonal antibodies was established by immunofluorescence microscopy and immunoblotting analysis. Fifteen out of nineteen hybridoma cell lines secreted IgG monoclonal antibodies (MAbs) against mumps virus, and the remaining four secreted IgM. The isotypes of thirteen clones of 19 MAbs were IgG1, two were IgG2a, and four were IgM. Eight MAbs reacted with a 68 kDa nucleocapsid protein, six MAbs reacted with a 46 kDa phosphoprotein, and five MAbs reacted with a 42 kDa matrix protein.