Pathogenic characterization of Erysipelothrix rhusiopathiae Met-203 type SpaA strains from chronic and subacute swine erysipelas in Japan.

To characterize the Erysipelothrix rhusiopathiae Met-203 type surface protective antigen (Spa) A strains causing swine erysipelas in Japan, the nucleotide sequence of the hypervariable region of the spaA gene was determined in 80 E. rhusiopathiae (serotype 1a) isolates collected from pigs with chronic and subacute swine erysipelas in 14 prefectures in 2008-2014. In this study, 14 (17.

Serological studies of infectious bronchitis vaccines against Japanese field isolates of homologous and heterologous genotypes.

The genetic diversity of the partial S1 gene involving the hyper variable region for infectious bronchitis (IB) vaccine strains in Japan were compared with those of IB virus isolated from the field in Japan. Field isolates have mainly been classified into three major genotypes, JP-I, JP-II and JP-III, since 2003; however, the 4/91 genotype was detected from recent field isolates in Japan. The virus neutralization (VN) activity with vaccine immunized serum was investigated to evaluate the protective effects of vaccines against Japanese field isolates.

Genetic analysis of the S1 gene of 4/91 type infectious bronchitis virus isolated in Japan.

S1 gene sequences for infectious bronchitis virus (IBV) strains of the 4/91 genotype (commonly called 793B) isolated from field outbreaks in Japan were analyzed to ascertain the relationship to 4/91 vaccine strain. Three field isolates (JP/Wakayama/2003, JP/Iwate/2005 and JP/Saitama/2006) from flocks not immunized with a 4/91 type live IBV vaccine and one isolate (JP/Wakayama-2/2004) from a flock immunized with a 4/91 type live vaccine were examined. The amino acid identities among JP/Wakayama/2003, JP/Iwate/2005 and JP/Saitama/2006 were about 98%, whereas the identities to the 4/91 vaccine strain and JP/Wakayama-2/2004 were about 90%.

Isolation of 4/91 type of infectious bronchitis virus as a new variant in Japan and efficacy of vaccination against 4/91 type field isolate.

Among field isolates of infectious bronchitis virus (IBV) from recent outbreaks, some isolates that were classified into the 4/91 genotype, by analysis of the S1 gene, have been confirmed to be a new variant in Japan. To elucidate the characteristics of these isolates, pathogenicity in chicks and the efficacy of vaccines against this new variant were examined. Severe respiratory symptoms were observed in 4-day-old specific pathogen free chicks inoculated with a 4/91 genotype isolate, either JP/Wakayama/2003 or JP/ Iwate/2005; body weights 3 wk after inoculation were significantly lower than those of chicks inoculated with a 4/91 vaccine strain.

The pathogenicity of canine parvovirus type-2b, FP84 strain isolated from a domestic cat, in domestic cats.

Canine parvovirus type-2a (CPV-2a) and type-2b (CPV-2b) have recently been isolated from domestic cats. The pathogenicity of CPV-2b in domestic cats is still unclear. In this study, we performed infection tests to examine the pathogenicity of CPV-2b, FP84 strain, isolated from a domestic cat.

Establishment of a potency test by ELISA for a rabies vaccine for animal use in Japan.

The ELISA we developed was able to determine the antigen content and was suitable for a potency test, and we described a relative potency assay method which determines the potency of test vaccines by comparing the ELISA value of a test vaccine to that of a reference vaccine. In the present study, we standardized the reference vaccine used for determining the potencies of test vaccines, and established a potency test by ELISA. We evaluated the proposed reference vaccine by the neutralizing antibody responses in dogs after vaccination, by the challenge protection test in guinea pigs (GP potency test), which is the earlier official potency test used in Japan, and by the NIH potency test, which is widely used throughout the world.

Functional analysis of an epitope in the S2 subunit of the murine coronavirus spike protein: involvement in fusion activity.

The monoclonal antibody (MAb) 5B19.2, which has virus-neutralizing and fusion inhibition activities, binds to an epitope (S2A) consisting of nine hydrophobic amino acids in the S2 subunit of the mouse hepatitis virus (MHV) spike (S) protein. This suggests that the S2A epitope may be involved in binding the virus to the MHV receptor and/or in virus-cell fusion.