RESUMO
Lentiviruses, among which is caprine arthritis encephalitis virus (CAEV), are known to concomitantly assemble and bud at the plasma membrane of infected cells, in a C-type defined pathway. Electron microscopy analysis of CAEV-infected cells demonstrated viral particles budding at the plasma membrane and into intracellular membrane-surrounded vesicles. Furthermore, nonenveloped immature virus-like particles, resembling intracytoplasmic type-A particles (ICAPs), accumulated within the cytoplasm of those cells. Fractionation on sucrose density gradients of cytoplasmic lysates from CAEV-infected cells revealed that enveloped immature or mature viral particles had a density of 1.16--1.17 g/ml, whereas ICAPs sedimented at a density of 1.2--1.27 g/ml. Endogenous reverse transcriptase activity was only associated with the 1.16--1.17 g/ml density particles despite the presence of viral RNA in both populations. The intracellular enveloped particles were found to be infectious. The CAEV Gag precursor by itself was shown to direct assembly, budding, and release of immature virus-like particles when expressed in goat primary synovial membrane cells using the same pathways of assembly and budding as observed in CAEV-infected cells. These data suggest that CAEV assembly, driven by the Gag precursor, could unusually proceed via two simultaneous pathways characteristic of type-C and type-B/D retroviruses.
Assuntos
Vírus da Artrite-Encefalite Caprina/fisiologia , Montagem de Vírus , Replicação Viral , Animais , Vírus da Artrite-Encefalite Caprina/patogenicidade , Vírus da Artrite-Encefalite Caprina/ultraestrutura , Células Cultivadas , Produtos do Gene gag/metabolismo , Doenças das Cabras/virologia , Cabras , Infecções por Lentivirus/veterinária , Infecções por Lentivirus/virologia , Microscopia Eletrônica , Precursores de Proteínas/metabolismo , DNA Polimerase Dirigida por RNA/metabolismo , Membrana Sinovial/citologia , Membrana Sinovial/virologia , Vírion/metabolismo , Vírion/patogenicidade , Vírion/ultraestruturaRESUMO
This study demonstrated the presence of viral particles suggestive of arthritis-encephalitis virus through the clinic, serologic, pathologic, immunohistochemic and ultrastructural studies in dairy goats. In the postmortem studies the tissues used were: synovial membrane, lungs and mammary gland from goats with clinical signs characteristic of the disease and positive for serum antibodies to the virus.
Assuntos
Anticorpos Antivirais/sangue , Vírus da Artrite-Encefalite Caprina/isolamento & purificação , Doenças das Cabras/virologia , Cabras/virologia , Infecções por Lentivirus/veterinária , Animais , Vírus da Artrite-Encefalite Caprina/crescimento & desenvolvimento , Vírus da Artrite-Encefalite Caprina/imunologia , Vírus da Artrite-Encefalite Caprina/ultraestrutura , Encéfalo/virologia , Feminino , Doenças das Cabras/epidemiologia , Doenças das Cabras/imunologia , Cabras/imunologia , Técnicas Imunoenzimáticas , Infecções por Lentivirus/epidemiologia , Infecções por Lentivirus/imunologia , Infecções por Lentivirus/virologia , Pulmão/virologia , Masculino , Glândulas Mamárias Animais/virologia , México/epidemiologia , Microscopia Eletrônica , Membrana Sinovial/virologia , Cultura de VírusRESUMO
The possible neurotropism of ungulate lentivirus was examined in clinical cases. Brain and ganglion tissue samples were examined from six female goats with caprine arthritis encephalitis and from six healthy controls. Ultrastructural examination revealed typical cytoplasmic A type retrovirus particles in the neural tissue of the diseased does. None were seen in the respective controls. Furthermore, no budding or extracellular retrovirus particles were seen in any of the neural tissue samples examined.
