Petrovskis Ivars, Skrastina Dace, Jansons Juris, Dislers Andris, Bogans Janis, Spunde Karina, Neprjakhina Anastasija, Zakova Jelena, Zajakina Anna, Sominskaya Irina
Latvian Biomedical Research and Study Centre, Ratsupites 1, LV-1067 Riga, Latvia.
Vaccines (Basel). 2024 Mar 4;12(3):267. doi: 10.3390/vaccines12030267.
Virus-like particles (VLPs) offer an attractive possibility for the development of vaccines. Recombinant core antigen (HBc) of Hepatitis B virus (HBV) was expressed in different systems, and the expression system was shown to be effective for the production of HBc VLPs. Here, we used HBc of the HBV genotype G (HBc/G) as a technologically promising VLP carrier for the presentation of spike RBM and nucleocapsid protein-derived peptides of the SARS-CoV-2 Delta variant for subsequent immunological evaluations of obtained fusion proteins. The major immunodominant region (MIR) of the HBc/G protein was modified through the insertion of a receptor binding motif (RBM) from the S protein or B-cell epitope-containing peptide from the N protein. The C-terminus of the two truncated HBc/G proteins was used for the insertion of a group of five cytotoxic T lymphocyte (CTL) epitopes from the N protein. After expression in , the MIR-derived proteins were found to be insoluble and were recovered through step-wise solubilization with urea, followed by refolding. Despite the lack of correct VLPs, the chimeric proteins induced high levels of antibodies in BALB/c mice. These antibodies specifically recognized either eukaryotically expressed hRBD or bacterially expressed N protein (2-220) of SARS-CoV-2. CTL-epitope-containing proteins were purified as VLPs. The production of cytokines was analyzed through flow cytometry after stimulation of T-cells with target CTL peptides. Only a protein with a deleted polyarginine (PA) domain was able to induce the specific activation of T-cells. At the same time, the T-cell response against the carrier HBc/G protein was detected for both proteins. The neutralization of SARS-CoV-2 pseudotyped murine retrovirus with anti-HBc/G-RBM sera was found to be low.
病毒样颗粒(VLPs)为疫苗开发提供了一种有吸引力的可能性。乙型肝炎病毒(HBV)的重组核心抗原(HBc)在不同系统中表达,且该表达系统被证明对生产HBc VLPs有效。在此,我们使用HBV基因型G的HBc(HBc/G)作为一种具有技术前景的VLP载体,用于展示严重急性呼吸综合征冠状病毒2(SARS-CoV-2)Delta变异株的刺突受体结合基序(RBM)和核衣壳蛋白衍生肽,以便对获得的融合蛋白进行后续免疫评估。通过插入来自S蛋白的受体结合基序(RBM)或来自N蛋白的含B细胞表位的肽,对HBc/G蛋白的主要免疫显性区域(MIR)进行了修饰。两种截短的HBc/G蛋白的C末端用于插入一组来自N蛋白的五个细胞毒性T淋巴细胞(CTL)表位。在[具体表达系统未给出]中表达后,发现MIR衍生蛋白不溶,通过用尿素逐步溶解,随后复性来回收。尽管缺乏正确的VLPs,但嵌合蛋白在BALB/c小鼠中诱导了高水平的抗体。这些抗体特异性识别真核表达的人RBD或SARS-CoV-2的细菌表达的N蛋白(2 - 220)。含CTL表位的蛋白被纯化为VLPs。在用靶CTL肽刺激T细胞后,通过流式细胞术分析细胞因子的产生。只有一种缺失多聚精氨酸(PA)结构域的蛋白能够诱导T细胞的特异性激活。同时,两种蛋白均检测到针对载体HBc/G蛋白的T细胞反应。发现抗HBc/G - RBM血清对SARS-CoV-2假型化鼠逆转录病毒的中和作用较低。