RESUMO
Primary chicken embryo cell cultures were evaluated a s an alternate cell system for the production of attenuated Venezuelan equine encephalomyelitis (TC-83 strain) vaccine. The TC-83 strain virus was shown to remain stable during 10 serial passages in chicken embryo cell culture with regard to plaque size and morphology, virus yield, potency, and virulence for mice and hamsters.
Assuntos
Vírus da Encefalite Equina Venezuelana/imunologia , Vacinas Atenuadas , Vacinas Virais , Animais , Embrião de Galinha , Cricetinae , Técnicas de Cultura , Vírus da Encefalite Equina Venezuelana/crescimento & desenvolvimento , Vírus da Encefalite Equina Venezuelana/patogenicidade , Estudos de Avaliação como Assunto , Coração Fetal , Cobaias , Imunoquímica , Camundongos , VirulênciaRESUMO
Envelope components were separated from Venezuelan, Eastern, and Western equine encephalomyelitis viruses after treatment of the virions with detergent. Vaccines prepared from the envelope component were capable of stimulating mice to produce humoral antibodies. Protective efficacy studies were performed using mono-, di-, and trivalent vaccine combinations. These elicited varying degrees of homologous protection, and Eastern and Venezuelan equine encephalomyelitis envelope products appeared to confer protection to mice challenged with Western equine encephalomyelitis virus.
Assuntos
Vírus da Encefalite Equina do Leste/imunologia , Vírus da Encefalite Equina Venezuelana/imunologia , Vírus da Encefalite/imunologia , Vacinas Atenuadas , Vacinas Virais , Animais , Anticorpos Antivirais/análise , Formação de Anticorpos , Vírus da Encefalite Equina do Leste/efeitos dos fármacos , Vírus da Encefalite Equina Venezuelana/efeitos dos fármacos , Encefalite por Arbovirus/prevenção & controle , Imunização , Camundongos , Polietilenoglicóis/farmacologiaRESUMO
Polyacrylamide gel electrophoretic examination of viruses selected from the Venezuelan equine encephalomyelitis (VEE) complex revealed distinct strain to strain differences in profiles of the two virion envelope proteins. The core protein was identical in all viruses tested. We detected five electrophoretic patterns into which the virus strains could be classified and these were designated alpha (alpha), beta (beta), gamma (gamma), delta (delta), and episolon (episolon). Isolates representing variant E of subtype I exhibited a profile characterized by only one apparent envelope band. The epizootic subtypes I-A, I-B, I-C and the sylvatic subtype II viruses contained at least two envelope proteins which differed in molecular weight according to virus strain but which were not necessarily specific for antigenic variety. These results generally, though not uniformly, support the serologic classification of the VEE virus complex and suggested that the usefulness of the classification scheme could be complemented by the inclusion of biochemical criteria.
Assuntos
Vírus da Encefalite Equina Venezuelana/classificação , Hemaglutininas Virais/isolamento & purificação , Proteínas Virais/isolamento & purificação , Animais , Eletroforese em Gel de Poliacrilamida , Vírus da Encefalite Equina Venezuelana/imunologia , Vírus da Encefalite Equina Venezuelana/isolamento & purificação , Imunodifusão , Camundongos , Camundongos Endogâmicos/imunologia , Peso Molecular , Coelhos/imunologia , Cultura de VírusRESUMO
The development of a new diagnostic procedure for the identification of Venezvelan, eastern and western equine encephalomyelitis (VEE, EEE, WEE) viruses is described. The procedure utilizes virus precipitation with reference fluorescein-conjugated gamma globulin, followed by cellulose acetate electrophoresis. Clinical specimens containing varying concentrations of virus yielded, in primary duck embryo cell culture, sufficient virus for detection within 22 to 44 hours. Identification of VEE, EEE and WEE virus in specimens was accomplished by microprecipitation within this time. In contrast to conventional identification methods, our procedure eliminates the cost of utilizing laboratory animals and considerably reduces the time required for virus identification.
Assuntos
Precipitação Química/métodos , Vírus da Encefalite Equina Venezuelana/isolamento & purificação , Vírus da Encefalite Equina do Oeste/isolamento & purificação , Vírus da Encefalite/isolamento & purificação , Encefalomielite Equina/microbiologia , Animais , Anticorpos Antivirais , Antígenos Virais , Células Cultivadas , Testes de Fixação de Complemento , Patos , Eletroforese , Embrião de Mamíferos , Embrião não Mamífero , Fluoresceínas , Testes de Inibição da Hemaglutinação , Soros Imunes , Coelhos/imunologia , Fatores de Tempo , Ensaio de Placa Viral , Cultura de Vírus , gama-GlobulinasRESUMO
Three viral proteins were separated from the TC-83 strain of Venezuelan equine encephalomyelitis virus by discontinuous polyacrylamide gel electrophoresis after disruption with sodium dodecyl sulfate and beta-2-mercaptoethanol. These proteins were inoculated into rabbits and the resultant antisera were tested for immunological activity by gel precipitation, plaque reduction neutralization, hemagglutination inhibition (HI), complement fixation, fluorescence microscopy, and mouse protection studies. All proteins were capable of stimulating precipitating antibody in rabbits, but the largest protein (VP 1), which is contained in the envelope, stimulated the production of detectable neutralizing and HI antibody against the intact virion. The other two proteins yielded little or no neutralizing or HI antibody.
Assuntos
Vírus da Encefalite Equina Venezuelana/análise , Proteínas Virais/análise , Animais , Antígenos Virais/análise , Testes de Fixação de Complemento , Eletroforese em Gel de Poliacrilamida , Vírus da Encefalite Equina Venezuelana/imunologia , Encefalomielite Equina/prevenção & controle , Imunofluorescência , Testes de Inibição da Hemaglutinação , Soros Imunes , Imunidade Materno-Adquirida , Imunodifusão , Injeções Subcutâneas , Mercaptoetanol , Camundongos , Testes de Neutralização , Coelhos/imunologia , Dodecilsulfato de Sódio , Proteínas Virais/isolamento & purificaçãoRESUMO
Treatment of purified Venezuelan equine encephalomyelitis virus with the nonionic detergent Triton X-100 permitted spearation of the envelope from the core component. The isolated envelope was a noninfectious immunogen which reacted in hemagglutination, hemagglutination inhibition, complement fixation, and neutralization serological reactions.
Assuntos
Antígenos Virais/isolamento & purificação , Vírus da Encefalite Equina Venezuelana/imunologia , Aminoácidos , Animais , Antígenos Virais/análise , Linhagem Celular , Embrião de Galinha , Testes de Fixação de Complemento , Cricetinae , Técnicas de Cultura , Eletroforese em Gel de Poliacrilamida , Encefalomielite Equina/prevenção & controle , Glucosamina , Testes de Inibição da Hemaglutinação , Testes de Hemaglutinação , Soros Imunes , Imunodifusão , Rim , Camundongos , Microscopia Eletrônica , Testes de Neutralização , Tensoativos , Trítio , Ultracentrifugação , Cultura de VírusRESUMO
Small- and large-plaque variants of a Florida strain (Fe 3-7c) of Venezuelan equine encephalomyelitis virus were studied in vivo and in vitro. The small-plaque variant was less virulent in mice, hamsters, and guinea pigs than the large-plaque variant. The variants could be distinguished by calcium phosphate chromatography. The implications of plaque variants within a mixed virus population are discussed.
Assuntos
Encefalomielite Equina/imunologia , Vírus da Encefalomiocardite/imunologia , Animais , Encéfalo/microbiologia , Fosfatos de Cálcio , Cromatografia , Cricetinae , Variação Genética , Cobaias/imunologia , Testes de Inibição da Hemaglutinação , Soros Imunes , Imunodifusão , Dose Letal Mediana , Camundongos , Testes de Neutralização , VirulênciaRESUMO
The rapid onset and persistence of homologous and heterologous protection induced by attenuated Venezuelan equine encephalomyelitis (VEE) vaccine (TC-83) were studied in the hamster, by using challenge response as the index of protection. At 8 hr postvaccination with 10(3) median immunizing doses of TC-83 vaccine, 15 to 20% of animals were protected against challenge with VEE virus as well as Eastern and Western equine encephalomyelitis viruses. The percentage of protection increased with time postvaccination until 80 to 90% homologous and heterologous protection was achieved by 18 hr postvaccination. Temporal studies indicated that early protection (days 1 to 6) correlated with vaccine viremia, and that the percentage of protection against heterologous challenge decreased with the cessation of viremia. Data are presented to indicate that the early protection phenomenon is one of interference, since little or no replication of a challenge virus occurred when it was administered during the vaccine viremia stage.
Assuntos
Vírus da Encefalite Equina Venezuelana/imunologia , Encefalomielite Equina/prevenção & controle , Vacinas Virais , Animais , Formação de Anticorpos , Cricetinae , Vírus da Encefalite Equina Venezuelana/isolamento & purificação , Vírus da Encefalite Equina do Oeste/imunologia , Vírus da Encefalite Equina do Oeste/isolamento & purificação , Vírus da Encefalite/imunologia , Vírus da Encefalite/isolamento & purificação , Encefalomielite Equina/sangue , Encefalomielite Equina/imunologia , Testes de Inibição da Hemaglutinação , Imunização , Injeções Intraperitoneais , Fatores de Tempo , Vacinas Virais/administração & dosagemRESUMO
Column chromatography of selected Venezuelan equine encephalomyelitis (VEE) viruses on calcium phosphate gel offered a simple and reproducible method for examination of biochemical characteristics and relatedness of strains within the VEE complex. Members of antigenic subgroup I demonstrated a series of elution profiles within a narrow range of 0.22 to 0.25 M phosphate buffer. Members of antigenic subgroups II, III, and IV differed substantially among themselves and viruses of antigenic subgroup I. These differences in elution behavior may contribute to understanding of observed differences in biological behavior and antigenic variation among VEE viruses.