[Use of microfiltration and gel filtration technics for purifying and concentrating the Venezuelan equine encephalomyelitis virus]. / Primenenie mikrofil'tratsionnoi i gel'-fil'tratsionnoi tekhniki dlia ochistki i kontsentrirovaniia virusa venesuél'skogo éntsefalomielita loshadei.

A system for purification and concentration of Venezuelan equine encephalomyelitis (VEE) virus omitting large-scale ultracentrifugation was developed. The first step consists in prefiltration through large pore nuclear filters (NF) to remove large particle admixtures from the virus-containing fluid. In the second step, the resulting filtrage undergoes concentrating microfiltration through small pore NF. In this way the virus, but not total protein, is concentrated approximately 30-fold without any loss of biological activity. For VEE virus purification the next step uses gel filtration chromatography in a column with chemically modified macropore silica. In this stage, the purification factor by protein is approximately 100-fold and virus yield reaches 40%. It is suggested that the procedure used be applied for purification and concentration of a wide range of enveloped viruses.

[Isolation of glycoproteins of the Venezuelan equine encephalomyelitis virus and an evaluation of their immunogenic activity]. / Vydelenie glikoproteidov virusa venesuél'skogo éntsefalomielita loshadei i otsenka ikh immunogennoi aktivnosti.

Isolation of purified Venezuelan equine encephalomyelitis virus glycoproteins by means of a new Soviet nonionic detergent, MESK, is described. The MESK detergent was shown to permit isolation of approximately 70% of virus particle glycoproteins. The resulting preparation had a high hemagglutinating activity, contained no admixtures of foreign proteins and was not infectious. The study of the immunogenicity of purified glycoproteins in experimental mice and rabbits showed them to be capable of inducing high levels of serum antibodies. The immunogenicity of the isolated glycoproteins was comparable to their immunogenicity as components of virus particles. Treatment of the virus with MESK detergent also yielded preparations with predominant content of capsid protein. The described procedure for disintegration and purification of viral proteins is technologically simple and may be the basis for manufacture of a subunit vaccine. The resulting material may also be used for preparation of diagnosticums and in laboratory studies.

[Characteristics of the ecology of the eastern equine encephalomyelitis virus in the Republic of Cuba]. / Nekotorye osobennosti ékologii virusa vostochnogo éntsefalomielita loshadei v Republike Kuba.

Virologic and serological surveys of wild vertebrates carried out in various provinces of Cuba demonstrated definitely that birds were the main hosts of eastern equine encephalomyelitis (EEE) virus in this territory. Fifteen strains of this virus were isolated from 8 species of birds belonging to 5 orders. Isolation of EEE virus from the blood of the endemic genus of iguanas indicates a certain role of cold-blooded animals in the ecology of this agent. Active EEE virus foci have been found in 4 provinces of the Republic of Cuba: Pinar del Rio, Havana, Matanzas and Las Villas. Isolation of a number of EEE virus strains from sick horses during an epizootic in the latter province confirmed the importance role of this agent in the infectious pathology of domestic animals in Cuba. The experimental results suggest that in Cuba there occur at least two types of foci of this infection: forest and water-littoral (fresh-water swamps and lakes, and sea coast with mangrove forests).