PDF(Pubmed)
Abstract：
A chimeric protein, formed by two fragments of the conserved nucleocapsid (N) and S2 proteins from SARS-CoV-2, was obtained as a recombinant construct in Escherichia coli. The N fragment belongs to the C-terminal domain whereas the S2 fragment spans the fibre structure in the post-fusion conformation of the spike protein. The resultant protein, named S2NDH, was able to form spherical particles of 10 nm, which forms aggregates upon mixture with the CpG ODN-39M. Both preparations were recognized by positive COVID-19 human sera. The S2NDH + ODN-39M formulation administered by the intranasal route resulted highly immunogenic in Balb/c mice. It induced cross-reactive anti-N humoral immunity in both sera and bronchoalveolar fluids, under a Th1 pattern. The cell-mediated immunity (CMI) was also broad, with positive response even against the N protein of SARS-CoV-1. However, neither neutralizing antibodies (NAb) nor CMI against the S2 region were obtained. As alternative, the RBD protein was included in the formulation as inducer of NAb. Upon evaluation in mice by the intranasal route, a clear adjuvant effect was detected for the S2NDH + ODN-39M preparation over RBD. High levels of NAb were induced against SARS-CoV-2 and SARS-CoV-1. The bivalent formulation S2NDH + ODN-39M + RBD, administered by the intranasal route, constitutes an attractive proposal as booster vaccine of sarbecovirus scope.
摘要：
嵌合蛋白，由SARS-CoV-2的保守核衣壳（N）和S2蛋白的两个片段形成，在大肠杆菌中作为重组构建体获得。N片段属于C末端结构域,而S2片段在刺突蛋白的融合后构象中跨越纤维结构。产生的蛋白质，名为S2NDH，能够形成10纳米的球形颗粒，其在与CpGODN-39M混合时形成聚集体。两种制剂均被阳性COVID-19人血清识别。通过鼻内途径施用的S2NDH+ODN-39M制剂在Balb/c小鼠中产生高度免疫原性。它在血清和支气管肺泡液中诱导交叉反应性抗N体液免疫，在Th1模式下。细胞介导的免疫（CMI）也很广泛，甚至对SARS-CoV-1的N蛋白也有阳性反应。然而,未获得针对S2区的中和抗体(NAb)或CMI。作为替代，RBD蛋白作为NAb的诱导物包含在制剂中。通过鼻内途径对小鼠进行评估后，S2NDH+ODN-39M制剂相对于RBD检测到明显的佐剂作用。针对SARS-CoV-2和SARS-CoV-1诱导高水平的NAb。双价配方S2NDH+ODN-39M+RBD,通过鼻内途径给药，构成了一个有吸引力的建议作为加强疫苗的sbecovirus范围。
