Knowles Tamece T, Alleman A Rick, Sorenson Heather L, Marciano David C, Breitschwerdt Edward B, Harrus Shimon, Barbet Anthony F, Bélanger Myriam
Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610, USA.
Clin Diagn Lab Immunol. 2003 Jul;10(4):520-4. doi: 10.1128/cdli.10.4.520-524.2003.
Canine monocytic ehrlichiosis, caused by Ehrlichia canis or Ehrlichia chaffeensis, can result in clinical disease in naturally infected animals. Coinfections with these agents may be common in certain areas of endemicity. Currently, a species-specific method for serological diagnosis of monocytic ehrlichiosis is not available. Previously, we developed two indirect enzyme-linked immunosorbent assays (ELISAs) using the major antigenic protein 2 (MAP2) of E. chaffeensis and E. canis. In this study, we further characterized the conservation of MAP2 among various geographic isolates of each organism and determined if the recombinant MAP2 (rMAP2) of E. chaffeensis would cross-react with E. canis-infected dog sera. Genomic Southern blot analysis using digoxigenin-labeled species-specific probes suggested that map2 is a single-copy gene in both Ehrlichia species. Sequences of the single map2 genes of seven geographically different isolates of E. chaffeensis and five isolates of E. canis are highly conserved among the various isolates of each respective ehrlichial species. ELISA and Western blot analysis confirmed that the E. chaffeensis rMAP2 failed to serologically differentiate between E. canis and E. chaffeensis infections.
由犬埃立克体或恰菲埃立克体引起的犬单核细胞埃立克体病可导致自然感染动物出现临床疾病。在某些地方流行区，这些病原体的混合感染可能很常见。目前，尚无用于单核细胞埃立克体病血清学诊断的种特异性方法。此前，我们利用恰菲埃立克体和犬埃立克体的主要抗原蛋白2（MAP2）开发了两种间接酶联免疫吸附测定（ELISA）。在本研究中，我们进一步表征了MAP2在每种生物体的不同地理分离株中的保守性，并确定恰菲埃立克体重组MAP2（rMAP2）是否会与犬埃立克体感染的犬血清发生交叉反应。使用地高辛标记的种特异性探针进行的基因组Southern印迹分析表明，map2在两种埃立克体中均为单拷贝基因。恰菲埃立克体七个地理上不同分离株和犬埃立克体五个分离株的单个map2基因序列在各自埃立克体物种的不同分离株中高度保守。ELISA和Western印迹分析证实，恰菲埃立克体rMAP2在血清学上无法区分犬埃立克体感染和恰菲埃立克体感染。
