Experimentelle Untersuchungen �ber das Virus der origin�ren Schweinepocken

Recombinant swinepox virus expressing beta-galactosidase: investigation of viral host range and gene expression levels in cell culture

Swinepox virus (SPV) has been proposed as a potential vector for generating recombinant vaccines for swine. However, little is known about important aspects of SPV biology, such as the functionality of SPV promoters or the host range of SPV. Using a transient expression assay, well-characterized vaccinia virus promoters were shown to be active in cells infected with SPV. A recombinant SPV expressing beta-galactosidase (beta-gal) was constructed and characterized. The E. coli LacZ gene was placed under the control of a strong vaccinia synthetic early/late promoter and was inserted by homologous recombination in a noncoding region of the SPV genome. The recombinant SPV expressing beta-gal was used to characterize the host range of the virus by measuring protein expression and virus production in different cell lines. In general, SPV expressed more protein and grew more efficiently than vaccinia virus in porcine cell lines. Surprisingly, the recombinant SPV was able to infect and replicate in several cell lines of nonswine origin. The virus directed regulated early and late gene expression of beta-gal in those cells and formed blue plaques in cell monolayers in the presence of X-gal. Upon infection with the recombinant SPV, there was a significant level of viral replication, and the virus can be serially passaged in some nonswine cell lines. The data presented suggest that despite the strict host tropism of SPV, the virus exhibits a relatively broad host range in cell culture.

Cross-reactivity between cowpox and vaccinia viruses with monoclonal antibodies. Brief report

Hybridoma cell lines producing monoclonal antibodies against cowpox virus (CPV) and vaccinia virus (VV) were established to examine the specific and cross-reactive antigenic determinants of these viruses. Monoclonal antibodies against CPV (LB red strain) and VV (Lister strain and Ikeda strain) were classified into several groups on the basis of the results of immunofluorescence and haemagglutination inhibition tests. It was suggested that the groups defined above include the group of antibodies reacting with each of known major antigens of poxvirus, i.e. nucleoprotein (NP) antigen, heat labile and stable complex (LS) antigen, haemagglutinin (HA), cell surface antigen (CSA) and type A inclusion body (A).

Ultrastructural aspects of experimental swinepox with special reference to inclusion bodies

A light and electron microscopic study was performed on pox-like epidermal lesions in an experimentally infected pig. Light microscopical investigation of semithin sections revealed the presence of nuclear vacuoles and of different types of cytoplasmic inclusions. In electron microscopical studies large numbers of both immature and mature virus particles and the cytological changes indicative of pox virus infection were observed. Various types of intra-cytoplasmic inclusions -- i.e. fibrillar inclusions, crystalloid-containing dense inclusions, complex membraneous inclusions and dense homogeneous inclusions -- were encountered in addition to viroplasms and nuclear vacuoles. Because of the presence of vacuoles in nuclei of stratum spinosum cells the diagnosis swine pox by swinepox virus was most probable. These nuclear vacuoles have not been described in swine pox caused by vaccinia virus, the only other known cause of pox in swine.

Swinepox. Virus isolation, experimental infections and the differentiation from vaccinia virus infections

The isolation of swinepox virus in primary pig kidney cell cultures is reported. The differentiation from vaccinia virus was possible with challenge infections of convalescent pigs and the use of the agar gel diffusion precipitation (AGDP) test and immuno-electroosmophoresis (IEOP). Using both immune precipitation tests reactions of identity were obtained between the heterologous antigens of swinepox and vaccinia viruses. A total of 829 pig sera from the field were tested for precipitating antibodies with the IEOP. Antibodies were detected in 65 (=7.8 per cent) of these serum samples.