[Physicochemical properties of Teschen disease virus RNA]. / Nekotorye fiziko-khimicheskie svoistva RNK virusa bolenzi Teshnena.

The specific infectivity of virion RNA of teschen disease virus in a sensitive PP cell culture was 4-5 lg TCD50/ml per 1 microgram RNA. When virion RNA was inoculated into cell cultures insusceptible to the native virus, the virus replicated to a titre of 2.0-3.5 lg TCD50/ml. The molecular weight of virion RNA determined by two independent methods was 2.7 x 10(6) daltons. Tm calculated from the curve of virion RNA melting temperature was 57 degrees C. The double-stranded replicative form of RNA recovered from virus-infected PP cells was shown to have sucrose gradient sedimentation coefficient of 20 S. The specific infectivity was 2-3 lg TCD50/ml per 1 microgram of RNA.

[Physicochemical properties of the Teschen disease virus]. / Fiziko-khimicheskie svoistva virusa bolezni Teshena.

The physical stability of Teschen disease virus (TDV) was tested. It was found that 8 M urea at 37 degrees C and 0.5% Tween-20 for 1-2 hours destroyed TDV with formation of morphologically distinct subunits. The morphology of TDV virions and its subunits formed under the effect of urea and Tween-20 was studied. Sedimentation constant (120 S) and the polypeptide composition of TDV were determined. In TDV, major polypeptides (VP1 less than or equal to 4) and minor polypeptides (VP1m and VP2m) were found their molecular weights being 82,000, 67,000, 35,000, 30,000, 77,000, and 46,000 daltons respectively.

[Isolation and identification of a virus causing abortions and stillbirths in swine (Preliminary report)]. / Izolirane i identifitsirane na virus, prichiniavashch aborti i m'rtvi razhdaniia pri svinete (Predvaritelno s'obshchenie)

A virus of the RNA type, having no lipid envelope, acid-fast and stable to heat, was isolated from an aborted fetus and from the kidney of a piglet of a lower viability at birth. It was readily cultured, multiplying quickly in primary cell cultures of pig kidney and in the SPEV cell line, producing a characteristic cytopathic effect. It gave no hemagglutination with human, chicken, and swine erythrocytes. Serologically, it was identified as a swine enterovirus of serotype I, identical with the viruses described as the etiologic agents of SMEDI.

Comparison of swine vesicular disease virus and Coxsackie B5 virus by serological and RNA hybridization methods.

The relatedness of swine vesicular disease virus (SVDV) and Coxsackie B5 virus has been studied by virus neutralization and immunodiffusion tests and by hybridization of the virus RNAs. Clearly defined differences between the two viruses were found by the three methods. Isolates of SVDV from several countries were very closely related but could be differentiated. Recent isolates of Coxsackie B5 virus also appeared to be similar but clear differences could be detected between these and the prototype (Faulkner) strain of the virus. The SVDV isolates were more closely related to the Faulkner strain than to the recent isolates of Coxsackie B5 virus. Perhaps of more importance, the Faulkner strain was more closely related to SVDV than it was to the recent Coxsackie B5 isolates. The significance of these observations in relation to the recent emergence of swine vesicular disease is discussed.

Molecular approach to the epidemiology of swine vesicular disease: correlation of variation in the virus structural polypeptides with serological properties.

Variation has been observed in the structural polypeptides of swine vesicular disease viruses isolated from the United Kingdom and Hong Kong. Despite the limited number of isolates examined, several distinct polypeptide patterns were obtained when the virus structural proteins were examined by polyacrylamide gel electrophoresis. Isolates from outbreaks in the United Kingdom which were known to be connected gave the same polypeptide pattern, whereas viruses with different polypeptide patterns could not be traced to a common source. The different polypeptide patterns were obtained consistently and were not altered by passage of the virus in tissue culture. In general, isolates with identical polypeptide patterns could not be distinguished by neutralization or antibody blocking tests or by competition radioimmunoassays. However, isolates with different polypeptide patterns could be differentiated by antibody blocking tests or radioimmunoassay. The correlation between the serological tests and the polyacrylamide gel electrophoresis analyses illustrates the value of analyzing structural polypeptides in the epidemiological study of swine vesicular disease.

Antigenic comparison of the polypeptides of foot-and-mouth disease virus serotypes and other picornaviruses.

The cross-reactivity of proteins coded for by the seven serotypes of foot-and-mouth disease virus (FMDV) was assessed by reaction of infected cell lysates with polyclonal and monospecific antisera against the structural and nonstructural proteins of FMDV type A12 strain 119ab. It was shown that the homologous polypeptides from most serotypes are antigenically related. The least cross-reactivity occurred between VP1, VP3, and the protease (3C) of type A12 and South African Territories types 1 and 3. There was also a reduced degree of reactivity of A12 VP1 serum with VP1 from some A subtypes and the other serotypes. Comparison of FMDV proteins with polypeptides from other picornaviruses by a radioimmune binding assay revealed a low level of reactivity of antisera against some A12 polypeptides with encephalomyocarditis virus (EMCV) infected cell lysates but no reactivity with bovine enterovirus type 1 and swine vesicular disease virus infected cells. The same EMCV proteins were immunoprecipitated by the various reactive A12 antisera, but the reaction was abolished if the lysate from EMCV infected cells was denatured prior to immunoprecipitation.