Antígenos de larva de Taenia solium em ELISA para diagnóstico da cisticercose bovina / Taenia solium metacestode antigens in ELISA for the diagnosis of bovine cysticercosis

Foram avaliados alguns parâmetros inerentes ao ELISA, por meio de ensaios de reatividade de soros-controle positivos e negativos para a cisticercose bovina com relação a três tipos de antígenos de larva de Taenia solium: total, de escólex e de membrana. As concentrações de antígeno de 0,25; 0,5; 1; 2 e 4µg por orifício, e as diluições de soro de 1:25, 1:50, 1:100 e 1:200, foram os parâmetros que menos influenciaram no desempenho do teste. A substância bloqueadora, o leite desnatado e as diluições de conjugado, 1:1.250, 1:2.500 e 1:5.000, representaram os melhores indicadores de desempenho do teste. Concluiu-se que essa combinação de critérios deve ser considerada no diagnóstico da cisticercose bovina, em atividades de rotina ou de padronização do referido teste, considerando os três antígenos de larva de T. solium estudados.

Some parameters of ELISA were evaluated using positive and negative bovine sera for cysticercosis and three types of antigens of Taenia solium larvae: total, scolex and membrane. The antigen concentrations (0.25; 0.5; 1; 2 and 4µg/well) and the serum dilutions (1:25, 1:50, 1:100 and 1:200) were the parameters that influenced less the test performance; while blocking substance, skimmed milk, and conjugate dilutions, 1:1.250, 1:2.500 and 1:5.000 were the best indexes of the test performance. It was concluded that this combination of criteria should be considered in the diagnosis of bovine cysticercosis, in routine diagnosis and for the ELISA test standardization.

Perfil fenotípico de linfócitos periféricos de bovinos de raças européias / Phenotypic profile of peripheral blood lymphocytes from European bovines

The phenotypic profile of bovine lymphocytes was evaluated in 18 bovines (Bos taurus) from three different breeds, being nine Holstein, six Hereford, and three Brown Swiss. All animals were free from ticks and hemoparasites, as determined after jugular vein blood sampling. The immunophenotypes of peripheral lymphocytes were evaluated by flow cytometry. Peripheral lymphocytes were exposed to bovine fluorescein-labeled monoclonal antibodies including anti-CD4, anti-CD8, and anti-purified bovine CD21 specificities. After lysing the erythrocytes with a commercial lysing solution (FACS TM ), the lymphocytes were washed, fixed, and evaluated by flow cytometry. Significant differences in the phenotypic profiles of peripheral lymphocytes among all breeds were found. Holstein animals showed a lower percentage of total T lymphocytes (CD4 and CD8) and higher percentage of B lymphocytes (CD21). In addition, the lymphocytes from Holstein animals showed a lower T/B ratio than the lymphocytes from Hereford animals. These results suggest the existence of different phenotypic profiles of peripheral lymphocytes from European breeds of cattle. Such differences may be related to the different pattern of immune response described for these breeds in the literature and may account to varying disease resistance among breeds.

Tentativa de transmitir Anaplasma marginale através de carrapatos Boophilus microplus / Attempted transmission of Anaplasma marginale by infected Boophilus microplus

O objetivo deste trabalho foi verificar a ocorrência da transmissäo transovariana de Anaplasma marginale em fêmeas de Boophilus microplus, que apresentaram multiplicaçäo da rickettsia em suas células intestinais. Larvas oriundas destas fêmeas foram colocadas em um bovino adulto, livre de infecçöes por hemoparasitos. O animal foi examinado diariamente através de tomada de temperatura, esfregaços sangüíneos e, semanalmente, através de exames sorológicos de Dot-ELISA. Durante 80 dias da fase experimental, o animal näo apresentou nenhum exame positivo. Os períodos de pré-postura, postura e a fase parasitária de fêmeas de B. microplus infectadas com A. marginale foram semelhantes às de fêmeas livres de infecçäo