ABSTRACT
Equine infectious anemia is an important infectious disease that affects equids worldwide. Control of the disease is currently based on detection of anti-p26 EIAV by Agar Gel Immunodiffusion (AGID). In this work, 62 animals were examined by AGID and nested-PCR using primers for the gag gene. Fifty-three samples (85.5%) were positive by nested-PCR, whereas only 33 samples (53%) were positive for AGID. Fifteen amplicons obtained by nested-PCR were sequenced and the aligned results subjected to phylogenetic analysis. The analysis suggests that the Brazilian EIAV form a cluster with WSU5, EIAVUK and Wyoming strains from United States.
Subject(s)
Equine Infectious Anemia/virology , Infectious Anemia Virus, Equine/isolation & purification , Animals , Brazil , Horses , Infectious Anemia Virus, Equine/classification , Infectious Anemia Virus, Equine/genetics , Phylogeny , Polymerase Chain Reaction , Viral Core Proteins/geneticsABSTRACT
The genome of the Caprine Arthritis-Encephalitis Virus (CAEV) encodes the polycistronic precursor protein p55(gag). Proteolytic cleavage of p55(gag) generates the viral core proteins. Some studies suggest that the CAEV p55(gag) protein contains epitopes or antigenic determinants for these core proteins. This work reinforces this hypothesis and demonstrates that monoclonal antibodies (MAbs) that are directed against the capsid protein (p28) of CAEV are also reactive against the precursor p55(gag) protein and the intermediate cleavage products, p44, p36 and p22. The major activity of the MAbs was directed against p28. The MAbF12 binding site in p28 was found to be a linear epitope with a structure that is stable after SDS treatment and remains unaltered after ß-mercaptoethanol (ß-ME) treatment. The MAbF12 binding site in the p55(gag), p36 and p22 proteins was found to be a linear epitope with cross-linked sulphide bonds. In conclusion, these findings suggest that the p28 epitope is presented differently from the epitope in the polycistronic precursor protein p55(gag). The highly immunogenic p28 contains a linear epitope that is detergent-stable and is not altered by ß-ME treatment, whereas the p55(gag) epitope contains a linear epitope susceptible to denaturing agents.
Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , Arthritis-Encephalitis Virus, Caprine/immunology , Capsid Proteins/immunology , Epitopes/immunology , Gene Products, gag/immunology , Animals , Female , Mice , Mice, Inbred BALB CABSTRACT
O vírus da Artrite-encefalite caprina (CAEV) é um Lentivírus de pequenos ruminantes, que causa uma doença crônica e progressiva, caracterizada por encefalomielite, mastite, pneumonia e artrite. O diagnóstico é baseado na detecção de anticorpos contra o vírus através da Imunodifusão em Gel de Agarose (IDGA), técnica sorológica de referência para CAEV, porém de baixa sensibilidade. O objetivo deste trabalho foi produzir um antígeno a partir da cultura de células de membrana sinovial caprina (MSC) infectadas com a CAEV, para ser utilizado em um teste diagnóstico (ELISA indireto). O antígeno foi obtido de culturas de células de MSC infectadas e posterior tratamento com SDS 0,1%. Amostras de soros caprinos (n=343) foram utilizadas para detectar a presença de anticorpos para CAEV pelo teste ELISA indireto e a técnica IDGA. Nessas amostras, o teste ELISA detectou 72 (21%) amostras positivas. Entretanto, o teste IDGA detectou 30 (8%) amostras positivas. O ELISA indireto também detectou precocemente uma soroconversão em 5 animais de um total de 13 controlados periodicamente durante 2 anos. A sensibilidade e a especificidade do teste ELISA com relação a IDGA foi de 73,3% e 84% respectivamente. Esse ELISA com o antígeno viral assim produzido mostrou-se efetivo, de baixo custo e sensível para o diagnóstico sorológico de anticorpos para CAEV.