Abdelbaky Hanan H, Fereig Ragab M, Nishikawa Yoshifumi
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan; Department of Animal Medicine, Faculty of Veterinary Medicine, South Valley University, Qena City, Qena 83523, Egypt.
Parasitol Int. 2018 Dec;67(6):675-678. doi: 10.1016/j.parint.2018.06.012. Epub 2018 Jun 27.
Dense granule protein 7 (NcGRA7) is a potent diagnostic antigen of Neospora caninum. Some studies have reported on the difficult expression, low yield, and variable degree of solubility of recombinant NcGRA7. We aimed to unravel the possible causes for these issues and tested NcGRA7 antigenicity in enzyme linked immunosorbent assays (ELISAs). The NcGRA7 coding sequence (217 amino acids) was split into five amino acid regions: NcGRA7m (27-217), NcGRA7m3 (27-160), NcGRA7m4 (27-135), NcGRA7m5 (161-190), and NcGRA7m6 (188-217). Three fragments, NcGRA7m, NcGRA7m3 and NcGRA7m4, exhibited high antigenic properties when tested against experimentally-infected mice and dog sera by ELISA. High levels of IgG2 antibodies against NcGRA7m3 were observed in field dog sera. In experimentally and naturally-infected cattle, the N. caninum-specific sera only reacted with NcGRA7m, indicating that this antigenic region differs among the three animal species. This study presents valuable information about the antigenic properties and topology of NcGRA7, and highlights its suitability for diagnostic purposes.
致密颗粒蛋白7（NcGRA7）是犬新孢子虫一种有效的诊断抗原。一些研究报道了重组NcGRA7表达困难、产量低以及溶解度变化程度大的问题。我们旨在揭示这些问题的可能原因，并在酶联免疫吸附测定（ELISA）中检测NcGRA7的抗原性。NcGRA7编码序列（217个氨基酸）被分成五个氨基酸区域：NcGRA7m（27 - 217）、NcGRA7m3（27 - 160）、NcGRA7m4（27 - 135）、NcGRA7m5（161 - 190）和NcGRA7m6（188 - 217）。通过ELISA检测，当用实验感染的小鼠和犬血清进行检测时，三个片段NcGRA7m、NcGRA7m3和NcGRA7m4表现出高抗原性。在野外犬血清中观察到针对NcGRA7m3的高水平IgG2抗体。在实验感染和自然感染的牛中，犬新孢子虫特异性血清仅与NcGRA7m反应，表明该抗原区域在这三种动物物种之间存在差异。本研究提供了关于NcGRA7抗原特性和拓扑结构的有价值信息，并突出了其在诊断目的方面的适用性。
