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Biomedical subjects

R Yanagawa

Publications and source records attributed to R Yanagawa.

At least 55 records · Page 3Linked to original sources
PubMed1987

Selection of antigenic variants from Leptospira interrogans serovar canicola by means of anti-canicola monoclonal antibody.

Antigenic variants were isolated from canicola by a single selection with anti-canicola monoclonal antibody CT-3. The variants were not identical to any serovars of serogroup Canicola and thought to be a new serovar. Variation frequency was calculated at 5.9 X 10(-4). The usefulness of monoclonal antibodies for selection of antigenic variants of leptospiras is discussed.

Agglutination Tests↗
PubMed1987

Purification, characterization and serological properties of a glycolipid antigen reactive with a serovar-specific monoclonal antibody against Leptospira interrogans serovar canicola.

A glycolipid antigen possessing a serovar-specific antigenic determinant of Leptospira interrogans serovar canicola was purified from a chloroform/methanol extract of the organism. The purification procedures included silicic acid column chromatography and preparative thin-layer chromatography (TLC). Antigenic activity was detected by a TLC-enzyme immunostaining technique using monoclonal antibody CT3, which specifically agglutinates serovar canicola and only weakly serovar sumneri but no other serovars of Leptospira. The purified glycolipid reacted with CT3 antibody, indicating that the glycolipid possessed a serovar-specific antigenic determinant. Infrared spectrum and proton nuclear magnetic resonance analyses showed that the glycolipid contained sugar and lipid moieties, which possessed amide linkages and an acetyl group. Gas-liquid chromatography-mass spectrometry analysis showed that the glycolipid contained two unknown sugars, one of which (unknown sugar II) appeared to be associated with the antigenic determinant specific for canicola. The serovar-specific antigenic determinant was destroyed by mild alkali treatment of the glycolipid. These findings suggested that the antigenic determinant was an alkali-labile moiety which may be related to the unknown sugar II.

Antibodies, Monoclonal↗
PubMed1986

Antigenic mapping and functional analysis of the F protein of Newcastle disease virus using monoclonal antibodies.

Twelve monoclonal antibodies to the F protein of a velogenic strain of Newcastle disease virus (NDV) were established. Each of these antibodies inhibited virus-induced plaque formation in BHK-21 cells. Seven antibodies neutralized viral infectivity in eggs; thus, antigenic variants could be selected with these antibodies and used for antigenic mapping. Based on the reactivity of the antigenic variants with the antibodies used in selection, 4 distinct antigenic sites (I-IV) were defined on the F protein molecule. In competitive binding assay, sites II and III were found to be spatially close to each other. Each antibody to sites I, II and III inhibited both virus-induced hemolysis of chicken erythrocytes and syncytium formation of BHK-21 cells. On the other hand, some of the antibodies to site IV selectively inhibited either hemolysis or cell fusion. This finding may indicate that the fusion of the viral envelope with erythrocytes and host cell membrane is modulated through different ways. Comparative analysis of different NDV strains using monoclonal antibodies to each of the different antigenic sites showed that the antigenicity of the F protein is highly conserved.

Animals↗
PubMed1986

Spin-labeling of influenza virus hemagglutinin permits analysis of the conformational change at low pH and its inhibition by antibody.

To study the conformational changes in the hemagglutinin (HA) molecule of A/seal/Mass/1/80 (H7N7) (Seal) influenza virus at low pH, a spin-labeling method was used. This method also permits study of antibody interaction with the HA. A synthetic nitroxide compound was used for spin-labeling of tyrosine residues of the isolated HA molecule. Electron spin resonance (ESR) spectra of the spin-labeled HA at various pH values indicated that a conformational transition occurred under acidic conditions, and around pH 5.8 the HA molecule has maximal flexibility. Since virus-induced hemolysis occurs optimally at pH 5.8-5.9, the HA molecule in the maximally flexible conformation is considered to mediate membrane fusion. The ESR spectra of the antibody-bound HA at various pH values revealed that monoclonal antibodies to different regions on the molecule may inhibit the conformational change by different modes. One antibody inhibited the changes in the HA that resulted in flexibility, while the other did not. These results support the assumption that monoclonal antibodies, which failed to inhibit hemagglutination of the virus yet neutralized viral infectivity, inhibited the fusion step in the viral replication process by interfering with a low pH-induced conformational change in the HA molecule (Kida, H., Webster, R.G. and Yanagawa, R. (1983) Arch. Virol. 76, 91-99).

Animals↗
PubMed1985

Is bivalent binding of monoclonal antibodies to different antigenic areas on the hemagglutinin of influenza virus required for neutralization of viral infectivity?

Biological activities of Fab fragments of monoclonal IgG antibodies to each of four nonoverlapping antigenic areas on the hemagglutinin molecule of A/seal/Massachusetts/1/80 (H7N7) influenza virus were examined. Fab fragments of the antibodies belonging to groups I and II neutralized viral infectivity. These Fab fragments inhibited hemagglutination of the virus and virus-induced hemolysis at pH 5.9. On the other hand, Fab fragments of groups III and IV antibodies showed neither neutralization nor hemolysis-inhibition activities, while intact IgG molecules of groups III and IV effectively neutralized viral infectivity and inhibited virus-induced hemolysis, as previously found. These IgG molecules scarcely or did not inhibit hemagglutination of the virus. Neutralization of viral infectivity, however, was observed when the virus was coated with Fab fragments of groups III and IV antibodies and then incubated with anti-Fab fragment antibodies. These findings suggest that bivalent binding of the IgG antibodies of groups III and IV is required for neutralization of viral infectivity through a proposed mechanism by which these antibodies interfere with a low pH-induced conformational change resulting in inhibition of the fusion step of the viral replication process.

Antibodies, Monoclonal↗
PubMed1985

Antigenic analysis of H4 influenza virus isolates using monoclonal antibodies to defined antigenic sites on the hemagglutinin of A/Budgerigar/Hokkaido/1/77 strain.

Three non-overlapping antigenic sites were defined on the hemagglutinin of avian influenza virus A/budgerigar/Hokkaido/1/77 (H4N6) by competitive binding assay of monoclonal antibodies to the virus and comparative antigenic analysis of variants selected with monoclonal antibodies. Antigenic relationship among 25 H4 influenza viruses of different bird origin was examined by ELISA with the monoclonal antibodies to each of defined antigenic sites. Two of the three antigenic sites contained epitopes specific to the H4 influenza viruses of budgerigar and mynah origin, and the remaining site contained an epitope which was cross-reactive with almost all of the H4 influenza viruses.

Animals↗
PubMed1985

Interference with a conformational change in the haemagglutinin molecule of influenza virus by antibodies as a possible neutralization mechanism.

A possible mechanism of neutralization of influenza virus by antibodies to the haemagglutinin molecule is proposed in addition to the generally accepted mechanism of blocking attachment to host cell receptors. This proposed mechanism involves interference with a low-pH-induced conformational change in the haemagglutinin molecule by bivalent binding of antibodies, which results in inhibition of the fusion step in the viral replication process.

Antibodies, Monoclonal↗
PubMed1985

Survival of Corynebacterium renale, Corynebacterium pilosum and Corynebacterium cystitidis in soil.

Survival of the causative agents of bovine pyelonephritis, Corynebacterium renale, C. pilosum and C. cystitidis, was examined at 30 degrees C in autoclaved soil. In the soil from a paddock, C. renale and C. cystitidis survived for 56 and 63 days, respectively, and C. pilosum for a longer period of at least 210 days. In soil from a pasture, sand from an athletic field and sea sand, the survival of these bacteria was of shorter duration.

Animals↗
PubMed1985

Adhesion of Corynebacterium renale and Corynebacterium pilosum to the epithelial cells of various parts of the bovine urinary tract from the renal pelvis to vulva.

The various parts of the bovine urinary tract, the renal pelvis, the ureter, the urinary bladder, the urethra, the vaginal vestibule and the vulva, were examined for the capacity of the epithelial cells to bind Corynebacterium renale and C. pilosum. C. renale adhered best to the epithelial cells of the vulva, and then to those of the ureter and renal pelvis. C. pilosum also adhered best to the epithelial cells of the vulva, followed by those of the vaginal vestibule. The results indicate that the most important target tissue for these bacteria may be the vulva, and the results correlate with the fact that C. renale frequently causes pyelonephritis and ureteritis, while C. pilosum causes the same diseases less frequently and behaves like normal flora of the vaginal vestibule.

Adhesiveness↗