Zhao Jincun, Wang Wei, Wang Wenling, Zhao Zhendong, Zhang Yan, Lv Ping, Ren Furong, Gao Xiao-Ming
Department of Immunology, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100083, China.
Clin Vaccine Immunol. 2007 Jul;14(7):839-46. doi: 10.1128/CVI.00432-06. Epub 2007 May 2.
Both the nucleocapsid (N) and the spike (S) proteins of severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) are able to induce strong humoral responses in humans following an infection. To compare the immunoglobulin G (IgG) responses to the S and N proteins of SARS-CoV in SARS patients during the manifestation/convalescent period with those during the postinfection period, serum samples were collected from hospitalized SARS patients within 6 weeks after the onset of illness (set 1; 57 sequential samples from 19 patients) or 2 to 3 months after their recovery (set 2; 33 postinfection samples from 33 subjects). Serum samples from 100 healthy blood donors (set 3), collected in 2002, were also included. The specific IgG response to whole virus, the fragment from positions 450 to 650 of the S protein (S450-650), and the full-length N protein of SARS-CoV were measured by enzyme-linked immunosorbent assays (ELISAs). Western blot assays were carried out to confirm the ELISA results. Fifty-one of the serum samples in set 1 (89%) bound to the N protein, a proportion similar to that which recognized whole virus (79%) and the S-protein fragment (77%). All 33 serum samples from set 2 were strongly positive for N-protein-specific IgG, while 27 (82%) were positive for anti-S450-650 IgG. Two of the serum samples from set 3 were strongly positive for anti-N-protein IgG but not anti-S450-650 IgG. Similar levels of IgG responses to the S and N proteins were observed in SARS patients during the manifestation and convalescent stages. In the postinfection period, however, a number of patients had much lower serum IgG levels against S450-650 than against the N protein.
严重急性呼吸综合征（SARS）相关冠状病毒（SARS-CoV）的核衣壳（N）蛋白和刺突（S）蛋白在感染人类后均能诱导强烈的体液免疫反应。为了比较SARS患者在发病/恢复期与感染后期针对SARS-CoV的S蛋白和N蛋白的免疫球蛋白G（IgG）反应，从发病后6周内住院的SARS患者（第1组；来自19名患者的57份连续样本）或康复后2至3个月（第2组；来自33名受试者的33份感染后样本）采集血清样本。还纳入了2002年采集的100名健康献血者的血清样本（第3组）。通过酶联免疫吸附测定（ELISA）检测针对SARS-CoV全病毒、S蛋白第450至650位片段（S450-650）和全长N蛋白的特异性IgG反应。进行蛋白质印迹分析以确认ELISA结果。第1组中的51份血清样本（89%）与N蛋白结合，这一比例与识别全病毒（79%）和S蛋白片段（77%）的比例相似。第2组的所有33份血清样本针对N蛋白特异性IgG均呈强阳性，而27份（82%）针对抗S450-650 IgG呈阳性。第3组的两份血清样本针对抗N蛋白IgG呈强阳性，但针对抗S450-650 IgG则不然。在SARS患者的发病期和恢复期观察到对S蛋白和N蛋白的IgG反应水平相似。然而，在感染后期，一些患者针对S450-650的血清IgG水平远低于针对N蛋白的水平。
