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- Author or Editor: Sylvia van Drunen Littel-van den Hurk x
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Abstract
Objective—To determine whether a herpesvirus isolated from the semen of a North American elk was related to bovine herpesvirus 1 (BHV-1).
Sample Population—Semen from 1 healthy bull elk and 2 subtypes of BHV-1 (BHV-1.1 and BHV-1.2).
Procedures—A virus with cytopathic and electron microscopic characteristics consistent with an alphaherpesvirus was isolated from elk semen, using fetal bovine kidney cells. Cross-neutralization assays were performed with antisera against BHV-1 and the elk herpesvirus (ElkHV). Restriction endonuclease digests of ElkHV DNA were compared with digests of BHV-1.1 and BHV-1.2 DNA. A portion of the ElkHV DNA polymerase gene was amplified with consensus primers by use of the polymerase chain reaction and sequenced. Sequence was compared with known sequences of other herpesviruses. An immunoperoxidase monolayer assay was used to determine reactivities of 22 BHV–1-specific monoclonal antibodies (mAb) against ElkHV. In vitro neutralizing activities of the reactive mAb were determined by use of a microneutralization assay.
Results—Results of cross-neutralization assays indicated that ElkHV was serologically related to BHV-1. Endonuclease digestion of ElkHV DNA generated fragments that were distinct from those of BHV-1. Nucleotide sequencing confirmed that ElkHV is an alphaherpesvirus closely related to but distinct from BHV-1. Six of 22 BHV–1-specific mAb reacted against ElkHV; 2 of these 6 also neutralized in vitro infectivity of ElkHV.
Conclusions and Clinical Relevance—ElkHV is antigenically and genetically distinguishable from BHV-1. However, the viruses are serologically related and share at least 6 antigenic determinants, one of which is a major neutralizing determinant. (Am J Vet Res 2000;61:1614–1618)
Abstract
Objective—To determine whether maternally derived antibodies interfere with the mucosal immune response following intranasal (IN) vaccination of newborn calves with a multivalent modified-live virus vaccine.
Design—Randomized controlled clinical trial.
Animals—23 newborn Holstein bull calves.
Procedures—Calves received colostrum and were assigned to group A (unvaccinated control calves), group B (IN vaccination on day 0), or group C (IN vaccination on days 0 and 35). Serum and nasal secretion sample (NSS) titers of antibodies specific for bovine herpesvirus 1, bovine viral diarrhea virus 1, and bovine viral diarrhea virus 2; WBC counts; and NSS interferon concentrations were determined up to day 77.
Results—Calves had high serum titers of maternally derived antibodies specific for vaccine virus antigens on day 0. High IgA and low IgG titers were detected in NSSs on day 0; NSS titers of IgA decreased by day 5. Group B and C NSS IgA titers were significantly higher than those of group A on days 10 through 35; group C IgA titers increased after the second vaccination. Serum antibody titers decreased at a similar rate among groups of calves. Interferons were not detected in NSSs, and calves did not develop leukopenia.
Conclusions and Clinical Relevance—IN vaccination of newborn calves with high concentrations of virus-neutralizing antibodies increased NSS IgA titers but did not change serum antibody titers. Revaccination of group C calves on day 35 induced IgA production. Intranasal vaccination with a modified-live virus vaccine was effective in calves that had maternally derived antibodies.