State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
Virol Sin. 2010 Feb;25(1):36-44. doi: 10.1007/s12250-010-3096-2. Epub 2010 Feb 12.
A group of SARS-like coronaviruses (SL-CoV) have been identified in horseshoe bats. Despite SL-CoVs and SARS-CoV share identical genome structure and high-level sequence similarity, SL-CoV does not bind to the same cellular receptor as for SARS-CoV and the N-terminus of the S proteins only share 64% amino acid identity, suggesting there are fundamental differences between these two groups of coronaviruses. To gain insight into the basis of this difference, we established a recombinant adenovirus system expressing the S protein from SL-CoV (rAd-Rp3-S) to investigate its immune characterization. Our results showed that immunized mice generated strong humoral immune responses against the SL-CoV S protein. Moreover, a strong cellular immune response demonstrated by elevated IFN-γ and IL-6 levels was also observed in these mice. However, the induced antibody from these mice had weaker cross-reaction with the SARS-CoV S protein, and did not neutralize HIV pseudotyped with SARS-CoV S protein. These results demonstrated that the immunogenicity of the SL-CoV S protein is distinct from that of SARS-CoV, which may cause the immunological differences between human SARS-CoV and bat SL-CoV. Furthermore, the recombinant virus could serve as a potential vaccine candidate against bat SL-CoV infection.
一组类似于非典的冠状病毒（SL-CoV）已在马蹄蝠中被发现。尽管 SL-CoV 和 SARS-CoV 具有相同的基因组结构和高度的序列相似性，但 SL-CoV 并不与 SARS-CoV 相同的细胞受体结合，并且 S 蛋白的 N 端仅共享 64%的氨基酸同一性，这表明这两种冠状病毒之间存在根本差异。为了深入了解这种差异的基础，我们建立了一种表达 SL-CoV S 蛋白的重组腺病毒系统（rAd-Rp3-S），以研究其免疫特征。我们的结果表明，免疫小鼠针对 SL-CoV S 蛋白产生了强烈的体液免疫反应。此外，这些小鼠还观察到高水平的 IFN-γ和 IL-6，表明存在强烈的细胞免疫反应。然而，这些小鼠产生的抗体与 SARS-CoV S 蛋白的交叉反应较弱，并且不能中和用 SARS-CoV S 蛋白假型化的 HIV。这些结果表明，SL-CoV S 蛋白的免疫原性与 SARS-CoV 不同，这可能导致人类 SARS-CoV 和蝙蝠 SL-CoV 之间的免疫学差异。此外，该重组病毒可以作为针对蝙蝠 SL-CoV 感染的潜在候选疫苗。
