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  • Author or Editor: A. E. Marshall x
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Objective—To determine whether a group of 3 genetic differences in the nonstructural protein (NS1) or 1 genetic difference in the structural protein (VP2) of Aleutian disease parvovirus (ADV) is responsible for an increase in the in vivo replication and pathogenicity of G/U-8, a chimera of ADV-G (nonpathogenic) and ADVUtah (pathogenic), compared with G/U-10.

Animals—32 eight-month-old female sapphire mink (Mustela vison).

Procedure—Chimeric viruses were constructed, propagated in vitro, and used to inoculate mink. Antiviral antibody responses, presence of serum viral nucleic acid, and serum gamma globulin concentrations were monitored for 120 days following inoculation. Histologic examination of the liver, kidneys, spleen, and mesenteric lymph nodes was performed after necropsy.

Results—A chimera containing only the 3 amino acid substitutions in NS1 did not elicit measurable responses indicative of replication or pathogenicity in inoculated mink. Serum antiviral antibody responses, frequency of detection of viral nucleic acid in serum, gamma globulin response, and histologic changes in mink inoculated with chimeras containing a valine residue at codon 352 (352V) of VP2 capsid were increased, compared with values from mink inoculated with chimeric viruses that did not contain 352V.

Conclusion and Clinical Relevance—A valine residue at codon 352 in the VP2 capsid protein of ADV affects in vivo viral replication and pathogenicity. This amino acid may be part of an incompletely defined pathogenic determinant of ADV. Further characterization of the pathogenic determinant may allow future development of focused preventive and therapeutic interventions for Aleutian disease of mink. (Am J Vet Res 2001;62:1658–1663)

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in American Journal of Veterinary Research


A study was conducted to determine whether subcomponent proteins (previously identified as BCSP20, BCSP31, and BCSP45, and the corresponding recombinant proteins rBCSP20, rBCSP31, and rBCSP45) that were recovered from the cell surface of Brucella abortus strain 19 were immunogenic and protective for mice when compared with Brucella cell surface protein (bcsp) and with a proteinase K-treated lipopolysaccharide (pklps) extracted from B abortus strain 2308. Protection was evaluated after challenge exposure with a virulent culture of B abortus strain 2308, using CD-I or BALB/c mice or both inoculated with vaccines of various combinations and concentrations, with and without pklps or bcsp. Protection was assessed by enumeration of splenic colony-forming units, reduced mean splenic weight relative to controls, and the relative serologic responses (immune response) in an elisa.

The general results indicate that bcsp, pklps, bcsp20, and bcsp31 are immunogenic or protective or both. Protectiveness was not observed for each of the recombinant proteins; however, results from the combined recombinant protein vaccine study suggest the immunogenicity of the recombinant proteins. The apparent immune-inducing properties of bcsp20 and bcsp31 are thought to be attributable to the presence of an immunogenic and protective bcsp fraction (possibly lipopolysaccharide) still associated. Serologic results support our conclusion that each of the recombinant protein vaccines did not induce a protective response comparable to that of bcsp or pklps, even when the subcomponents were combined.

Although the results suggest that the subcomponents of bcsp apparently induced partial protection, they are thought to be only a part of the antigens contained in bcsp that influence the serologic response. Our findings may serve as an experimental model to determine the mechanisms involved in the protective responses induced by Brucella antigens.

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in American Journal of Veterinary Research