http://repub.eur.nl/res/aut/11105/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/13812/ 2005-06-01T00:00:00Z The use of classical smallpox vaccines based on vaccinia virus (VV) is associated with severe complications in both naive and immune individuals. Modified vaccinia virus Ankara (MVA), a highly attenuated replication-deficient strain of VV, has been proven to be safe in humans and immunocompromised animals, and its efficacy against smallpox is currently being addressed. Here we directly compare the efficacies of MVA alone and in combination with classical VV-based vaccines in a cynomolgus macaque monkeypox model. The MVA-based smallpox vaccine protected macaques against a lethal respiratory challenge with monkeypox virus and is therefore an important candidate for the protection of humans against smallpox. http://repub.eur.nl/res/pub/3331/ 1987-01-01T00:00:00Z Sixteen monoclonal antibodies (Mcabs) were prepared against infectious bronchitis virus strain M41, all of them reacting with the peplomer protein. One of them, Mcab 13, was able to neutralize the virus and to inhibit hemagglutination. Competition binding assays allowed the definition of five epitopes, designated as A, B, C, D, and E, of which epitopes A and B are overlapping. Furthermore, the binding of Mcab 13 (epitope E) could be enhanced by the addition of Mcabs from group B, C, and D. A dot immunoblot assay was used to analyze the effect of denaturation on antibody recognition of the epitopes. Only the binding of Mcab 13 was affected, indicating that the epitope involved in neutralization and hemagglutination is conformation dependent. The epitopes A to D were highly conserved among IBV strains, while epitope E was specific for strains M41 and D3896. In this last strain, however, this epitope was not involved in neutralization. http://repub.eur.nl/res/pub/3289/ 1984-01-01T00:00:00Z http://repub.eur.nl/res/pub/3268/ 1983-01-01T00:00:00Z Twenty 5-fluorouracil-induced temperature-sensitive (ts) mutants of mouse hepatitis virus strain A59 were isolated from 1284 virus clones. Mutants were preselected on the basis of their inability to induce syncytia in infected cells at the restrictive temperature (40 degrees) vs the permissive temperature (31 degrees). Of these mutants, only those with a relative plating efficiency 40 degrees/31 degrees of 3 x 10(-3) or smaller were kept. Virus yields at 40 degrees compared to 37 degrees and 31 degrees (leakiness) were determined. Most mutants (16) were RNA-, i.e., unable to synthesize virus-specific RNA at the restrictive temperature. The other four were RNA+. No qualitative differences were detected in the virus-specific RNAs in cells infected with RNA+ ts-mutants, both at 31 degrees and 40 degrees. Virus-specific proteins present in cells infected with ts-171 (RNA-) and the RNA+-mutants (ts-43, ts-201, ts-209, and ts-279) were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of immunoprecipitates. No qualitative differences in the pattern of virus-specific cellular proteins were detected among the mutants except for an additional polypeptide of about 46,000 daltons in ts-209-infected cells. Finally, the neuropathogenic properties of eight of the mutants were investigated. Whereas 10(2) PFU of wild-type virus injected intracerebrally killed 50 to 100% of 4-week-old Balc/c mice within 1 week, the mutants were highly attenuated. A dose of 10(5) PFU lead to no or transient disease. However, 4 weeks after infection with ts-342, ts-43, or ts-201 obvious histological changes were observed in brain and spinal cord of clinically healthy mice.