Shunji Yamada

Cytocidal infection of hog cholera virus in porcine bone marrow stroma cell cultures.

Porcine bone marrow stroma cell (BMSC) cultures producing cells of granulocyte-lineage were established. Hog cholera (HC) virus ALD and Alfort strains replicated in the porcine BMSC cultures showing distinct cytopathic effect (CPE). The differentiation of granulocyte-lineage cells in the cultures ceased after infection with HC virus. Polyclonal antibody against the ALD strain inhibited completely the development of CPE of the both ALD and Alfort strains. Monoclonal antibodies (mAbs) specific to the ALD strain inhibited CPE of the ALD strain, while CPE of the Alfort strain was not affected by those mAbs, suggesting that CPE induced in the BMSC cultures is due to HC virus.

First isolation of border disease virus in Japan is from a pig farm with no ruminants

The first isolation of border disease virus (BDV) in Japan was from a pig farm of the farrow-to-finishing type that kept no small ruminants or cattle. The infection was detected in the course of sero-surveillance for classical swine fever virus (CSFV) in Japan. The infected pigs had no clinical symptoms of CSFV or other disease; nevertheless, a high sero-positive rate of 58.5% was identified. A persistently infected pig with the BDV was found and suspected to be the cause of sero-prevalence in the farm. The isolated BDV was genetically close to BDV strains from New Zealand, but there was no epidemiological evidence concerning the route(s) of the invasion into the farm.

A mutant of pseudorabies virus with deletion of glycoprotein gIII gene prepared from a Japanese isolate: It fails to agglutinate mouse erythrocytes

A mutant with deletion of the glycoprotein gIII gene was produced from a Japanese isolate of pseudorabies virus (PrV) and characterized. Viral titers of the mutant propagated in PK-15 cells were always lower than those of the parental virus. The parental virus agglutinated BALB/c mouse erythrocytes, whereas the deletion mutant showed no hemagglutinating activity. Pigs inoculated with the parental virus produced not only neutralizing but also hemagglutination-inhibiting antibodies. On the other hand, the mutant induced high titers of neutralizing antibody comparable to the parental virus but no hemagglutination-inhibiting antibody in inoculated pigs, suggesting that glycoprotein gIII is an essential component for hemagglutination of PrV. Finally, no evidence that the deletion mutant lost virulence for mice was obtained.