Expression of the S1 Protein for Recombinant SARS-CoV-2 Omicron Variants and Its Immunogenicity Evaluation
10.11969/j.issn.1673-548X.2024.08.024
- VernacularTitle:重组SARS-CoV-2 Omicron变异株S1蛋白的表达及免疫原性评价
- Author:
Huimin LU
1
;
Zihao WANG
;
Cheng BIAN
Author Information
1. 6501181昆明,中国医学科学院/北京协和医学院医学生物学研究所医学遗传学研究室
- Keywords:
SARS-CoV-2;
Recombinant protein vaccine;
Adjuvant;
Pseudovirus;
Neutralizing antibodies
- From:
Journal of Medical Research
2024;53(8):126-131
- CountryChina
- Language:Chinese
-
Abstract:
Objective To construct a eukaryotic expression vector for the SARS-CoV-2 Omicron BA.1 mutant S1 protein,ex-pressed in CHO-K1 cells to evaluate its immunogenicity,and investigate the adjuvant and antigen dosages.Methods The recombinant plasmid UCOE-Omi-S1 was constructed and transfected into CHO-K1 engineering cells for expression and purification.The recombi-nant S1 protein was confirmed using SDS-PAGE and Western blot.BALB/c mice were randomly divided into 12groups:PBS group,no adjuvant group(high,medium and low-dose groups),aluminum salt adjuvant control group,MF59 adjuvant control group,aluminum salt adjuvant experimental group(high,medium and low-dose groups),MF59 adjuvant experimental group(high,medium and low-dose groups).The solution in accordance with the required proportion of the group was injected intramuscular into the mice 3 times,the interval of 14days,and the blood was collected from the tail vein every 2 weeks,and the serum was separated 30days after the last immu-nization.Enzyme-linked immunosorbent assay(ELISA)was used to detect serum antibody levels and to neutralize pseudoviruses with SARS-CoV-2 prototype and SARS-CoV-2 Omicron BA.1 variant strains.Results After the expression of the target protein in CHO-K1 engineering cells,the expressed protein was observed at a relative molecular mass of approximately 70kDa and was identified as Omi-S1 protein by Western blot.The immune induction effect of the aluminum salt adjuvant group and MF59 adjuvant group was better than that of the no adjuvant group.There was no significant difference between the aluminum salt adjuvant group and the MF59 adjuvant group,but the MF59 adjuvant took effect more quickly.The immune induction effect of the high,middle,and low-dose groups was simi-lar at the 8th week,but the effect of the high-dose group was faster.Pseudovirus neutralization experiments showed that MF59 adjuvant experimental group exhibited higher levels of neutralizing antibodies against the Omicron variants than the aluminum salt adjuvant group.Conclusion This study successfully constructed a recombinant protein of Omicron S1 with good immunogenicity and generated a strong humoral immune response in mice,inducing high levels of neutralizing antibodies against SARS-CoV-2 pseudovirus.The adjuvant and antigen dosages of SARS-CoV-2 were preliminarily studied showed that a dose of less than 10μg of antigen dosages with MF59 adjuvant was found to be effective in inducing good immunity.These findings provide the experimental basis for the development of recombinant protein vaccines against SARS-CoV-2 variants.
