In vitro model for producing antigens of equine infectious anemia and bovine immunodeficiency-Zike viruses

L'absence d'un modèle cellulaire adéquat restreint la production d'anti gènes des virus de l'anémie infectieuse des équidés (VAIE) et de l'immuno- déficience bovine (VIB). Dans une première phase, le développement du modèle implique : 1) des cellules d'une lignée continue susceptibles au virus ; 2) une infection permanente ; 3) une production continue d'antigènes en milieu sans sérum. Dans une deuxième phase, les antigènes sont produits en grande quantité et sans interruption dans un bioréacteur. La première phase a été atteinte par l'infection permanente de deux lignées canines par le VAIE et le VIB, mais n'a pas été complétée avec le VIB à cause de l'absence d'épreuves sérologiques détectant les antigènes. La deuxième phase est encore à l'étude pour les deux virus.In vitro antigen production of equine infectious anemia (EIAV) and bovine immunodeficiency-like (BIV) viruses is hampered by the absence of adequate cellular models. The first step required in the development of such models depends on criteria such as : 1) viral permissiveness of cells in a continuous line ; 2) persistent infection ; 3) continuous production of antigen in a serum-free medium. The second step involves the large-scale production of antigen in a bioreator. The first step was achieved by initiating persistent infection of two canine cell lines by EIAV and BIV respectively. However, the method of BIV antigen production has not been completed due to the lack of adequate serological tests for detection of antigens. The second step involving both viruses is under study

Structural characterization and serological specificities of lipopolysaccharides from Salmonella enterica serovar Gallinarum biovar Pullorum standard, intermediate and variant antigenic type strains: Vet.Microbiol.

The structure and serological specificities of the lipopolysaccharides (LPSs) from Salmonella enterica serovar Gallinarum biovar Pullorum were studied to provide an improved basis for the distinction between antigenic types and the development of improved diagnostic tests. The structure of the LPS O-polysaccharide (O-PS) from S. Pullorum standard, intermediate and variant antigenic type strains was determined by mass spectrometry, nuclear magnetic resonance spectroscopy and chemical analysis. The LPS of the three strains shared a common structural repeating oligosaccharide unit containing d-mannose, l-rhamnose, d-galactose and d-tyvelose (1:1:1:1). The O-PS of the variant type LPS contained an additional d-glucose residue linked to the O-4 position of the d-galactose residue. The O-PS of the intermediate type LPS was partially the same as that of the variant LPS, however, the molar ratio of the d-glucose component was lower with respect to the other glycose components. Serological specificities of the three antigenic type LPSs were examined with anti-S. Pullorum LPS monoclonal antibodies (Mabs). On immunoblots, Mabs to the standard type O-PS reacted with high molecular mass (HMM) and low molecular mass (LMM) LPS from the standard strain, and with LMM but not HMM LPS from the variant strain. Monoclonal antibodies to the variant type O-PS reacted with HMM but not LMM LPS from the variant strain, and did not react with HMM or LMM LPS from the standard strain. On ELISA, the standard, intermediate and variant antigenic type strains were differentiated by the relative reactivity with the anti-LPS O-PS Mabs. Several of the anti-LPS O-PS Mabs were specific for S. Pullorum and other serogroup D1 Salmonella, and are potentially useful for the development of improved diagnostic tests for these organismsNRC publication: Ye

Structure of the O-polysaccharide of the lipopolysaccharide produced by Taylorella asinigenitalis type strain (ATCC 700933): Biochem.Cell Biol.

Taylorella asinigenitalis sp. nov is a nonpathogenic gram-negative bacterium recently isolated from the genital tract of male donkeys. The bacterium is phenotypically indistinguishable from Taylorella equigenitalis, a pathogen that is the cause of contagious equine metritis, a highly communicable venereal disease of horses. The structural analysis of the lipopolysaccharide produced by T. asinigenitalis sp. nov (ATCC 700933) demonstrated that its O-polysaccharide (O-PS) component is a linear unbranched polymer of repeating disaccharide units composed of 1,3-linked pyranosyl residues of 2,4-diacetamido-2,4-dideoxy-beta-D-quinovose (bacillosamine) and 2-acetamidino-2-deoxy-beta-D-glucuronic acid, and has the structure [-->3)-beta-D-QuipNAc4NAc-(1-->3)-beta-D-GlcpNAmA-(1-->]n. The chemical structure and serological characteristics of the T. asinigenitalis O-PS are distinct from those of the O-PS of the T. equigenitalis type strain, thus providing a cell-surface target macromolecule that can be used to distinguish pathogenic from nonpathogenic Taylorella sp. clinical isolatesNRC publication: Ye

The structure of the polysaccharide of the lipopolysaccharide produced by Taylorella equigenitalis type strain (ATCC 35865): Carbohydr.Res.

Taylorella equigenitalis is a Gram-negative bacterium that causes venereally transmitted contagious equine metritis (CEM), and its identification and differentiation from other bacteria and Taylorella species is an important requirement for the control of CEM infection. Based on the results of NMR and MS analysis, the antigenic O-polysaccharide (O-PS) component of the lipopolysaccharide (LPS) produced by the type strain T. equigenitalis (ATCC 35865) was found to be a linear polymer composed of a repeating disaccharide unit, containing partially amidated 2,3-diacetamido-2,3-dideoxy-alpha-L-guluronic and 2,3-diacetamido-2,3-dideoxy-beta-D-mannuronic acids, terminated with a 4-O-methylated non-reducing Gulp-NAc3NAcA residue, and has the structure [structure: see text]. The O-PS of the type strain T. equigenitalis LPS provides a specific antigenic marker for the discrimination of the pathogen from the related type strain of T. asinigenitalis sp. nov, a phenotypically indistinguishable non-pathogenic bacterium having a serologically and structurally unrelated LPS O-antigen. The analysis of a structurally unusual core oligosaccharide of the LPS is also reportedNRC publication: Ye

TREATMENT OF OOCYTES AND IN VITRO FERTILIZED EMBRYOS WITH MONOCLONAL ANTIBODIES AND GUINEA PIG COMPLEMENT FOR NEUTRALIZATION OF CONTAMINATING BOVINE HERPESVIRUS-1

The association of bovine herpesvirus-1 (BHV-1) with oocytes and in vitro fertilized (IVF) embryos after treatment with a mixture of three BHV-1 monoclonal antibodies (AB) and guinea pig complement (GPC) was investigated in a series of three experiments. Exposure of cumulus-oocyte complexes (COC) to BHV-1 (10(5) TCID50/ml) in the maturation medium for 22 h followed by treatment with the AB alone or with a mixture of AB and GPC prior to fertilization, yielded a total of 15% of resulting embryos free of the virus. When the cumulus-free oocytes/zygotes were treated with a mixture of AB and GPC after fertilization and then co-cultured in the medium containing bovine oviductal epithelial cells (BOEC), 88% of samples containing embryos (n = 70) were free of the virus. Application of the same treatment or GPC alone followed by the culture of zygotes in the medium without BOEC yielded all 40 samples containing 123 embryos free of the infectious virus. In addition, the Day-7 embryos exposed to BHV-1 and then treated with a mixture of AB and GPC were tested negative. In conclusion, these experiments suggest that BHV-1 contamination of zygotes and Day-7 IVF embryos may be neutralized by treatment with a mixture of AB and GPC or GPC alone. The results also show that it is advantageous to use the IVF embryo culture system free of supporting cells in order to increase the number of embryos free from the infectious virus