A microplate enzyme‐linked immunorsorbent assay for measuring antibody to Anaplasma marginale in cattle serum

Abstract

An enzyme-linked immunosorbent assay (ELISA) method is described for measuring antibody against Anaplasma marginale in cattle serum. This method was more sensitive and objective than a previously described ELISA method for A. marginale and possible reasons for this are discussed. All 83 cattle experimentally infected with A. marginale (81) or A. centrale (2) developed demonstrable specific antibody but the serums of 98.8% of 839 cattle from cattle tick-free areas did not react by ELISA; 378 serums containing antibody to Babesia bovis were tested for cross reactions in the A. marginale ELISA. There were no significant cross-reactions except when cattle had been inoculated at least twice with B. bovis-infected erythrocytes, presumably due to antibodies reacting with erythrocyte material in the ELISA antigen. The ELISA detected antibodies for more than 3 years after infection, at least 2 years longer than did a complement fixation test. When A. marginale infections in cattle were eliminated by long acting oxytetracycline, their serums ceased to react by ELISA. An ELISA score for serum antibody level was shown to have a statistically significant correlation with ELISA titre.

ELISA com MSP5 recombinante truncada para detecção de anticorpos contra Anaplasma marginale em bovinos

“…Nesses ensaios, provavelmente ocorreram contaminação dos antígenos com proteínas de eritrócitos, as quais podem reagir inespecificamente com anticorpos presentes no soro, resultando assim em reações falso positivas, que interferem diretamente na especificidade do teste (Barry et al 1986). …”

Comparison between indirect enzyme-linked immunosorbent assays for Anaplasma marginale antibodies with recombinant major surface protein 5 and initial body antigens

“…This indicates that contamination of IB antigen with erythrocyte proteins did not influence the performance of the IB ELISA. Crude antigen ELISAs with erythrocyte proteins has been incriminated for false-positive reactions, as result of reaction with anti-erythrocyte antibodies in the sera (Barry et al 1986). However, the crossed reactions probably occurred due to host immune reaction, because previously ELISA for detection of A. marginale antibodies displayed false positive reactions during acute phase of Babesia spp.…”

Comparação entre diversos antígenos para o diagnóstico de Anaplasma marginale por ELISA

“…Alguns ELISAs para o diagnóstico de A. marginale utilizam como antígeno lisado de corpúsculos iniciais da riquétsia parcialmente purificados de eritrócitos bovinos infectados (Barry et al 1986, Madruga et al 2000. No entanto, esses ensaios apresentam uma especificidade reduzida devido a reações falso positivas provocadas pela combinação de anticorpos anti-eritrócitos e proteínas eritrocíticas que possam estar contaminando o antígeno (Knowles et al 1996).…”