Research Department, China-Cuba Biotechnology Joint Innovation Center (CCBJIC) Lengshuitan District, Yongzhou City, 425000, Hunan, China.
R&D Department, Yongzhou Zhong Gu Biotechnology Co., Ltd., Yangjiaqiao Street, Lengshuitan District, Yongzhou City, 425000, Hunan, China.
Virol J. 2024 Nov 29;21(1):310. doi: 10.1186/s12985-024-02583-9.
The Hepatitis B core antigen (HBcAg) has been used as a carrier of several heterologous protein fragments based on its capacity to form virus-like particles (VLPs) and to activate innate and adaptive immune responses. In the present work, two chimeric proteins were designed as potential pancorona vaccine candidates, comprising the N- or C- terminal domain of SARS-CoV-2 nucleocapsid (N) protein fused to HBcAg. The recombinant proteins, obtained in E. coli, were named CN-1 and CND-1, respectively. The final protein preparations were able to form 10-25 nm particles, visualized by TEM. Both proteins were recognized by sera from COVID-19 convalescent donors; however, the antigenicity of CND-1 tends to be higher. The immunogenicity of both proteins was studied in Balb/C mice by intranasal route without adjuvant. After three doses, only CND-1 elicited a positive immune response, systemic and mucosal, against SARS-CoV-2 N protein. CND-1 was evaluated in a second experiment mixed with the CpG ODN-39 M as nasal adjuvant. The induced anti-N immunity was significantly enhanced, and the antibodies generated were cross-reactive with N protein from Omicron variant, and SARS-CoV-1. Also, an anti-N broad cellular immune response was detected in spleen, by IFN-γ ELISpot. The nasal formulation composed by CND-1 and ODN-39 M constitutes an attractive component for a second generation coronavirus vaccine, increasing the scope of S protein-based vaccines, by inducing mucosal immunity and systemic broad humoral and cellular responses against Sarbecovirus N protein.
乙型肝炎核心抗原 (HBcAg) 已被用作几种异源蛋白片段的载体,基于其形成病毒样颗粒 (VLPs) 和激活先天和适应性免疫反应的能力。在本工作中,设计了两种嵌合蛋白作为潜在的全冠疫苗候选物,包含 SARS-CoV-2 核衣壳 (N) 蛋白的 N 或 C 末端结构域融合到 HBcAg。在大肠杆菌中获得的重组蛋白分别命名为 CN-1 和 CND-1。最终的蛋白制剂能够形成 10-25nm 的颗粒,通过 TEM 观察到。两种蛋白均被 COVID-19 恢复期供体的血清识别;然而,CND-1 的抗原性倾向更高。通过鼻内途径向 Balb/C 小鼠免疫两种蛋白,无需佐剂。三次免疫后,只有 CND-1 引起针对 SARS-CoV-2 N 蛋白的全身性和黏膜性的阳性免疫反应。在第二项实验中,CND-1 与 CpG ODN-39M 混合作为鼻内佐剂进行评估。诱导的抗-N 免疫反应显著增强,产生的抗体与奥密克戎变异株和 SARS-CoV-1 的 N 蛋白发生交叉反应。此外,通过 IFN-γ ELISpot 在脾脏中检测到针对 N 蛋白的广泛细胞免疫反应。由 CND-1 和 ODN-39M 组成的鼻内制剂构成了第二代冠状病毒疫苗的有吸引力的成分,通过诱导黏膜免疫和针对 Sarbecovirus N 蛋白的全身性广泛体液和细胞反应,增加了基于 S 蛋白疫苗的范围。
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