Immunogenicity Evaluation of a SARS-CoV-2 BA.2 Subunit Vaccine Formulated with CpG 1826 plus alum Dual Adjuvant  

作　　者：Yuhan Yan Qiudong Su Yao Yi Liping Shen Shengli Bi 

机构地区：[1]National Institute for Viral Disease Control and Prevention,Chinese Center for Disease Control and Prevention,Beijing 102206,China

出　　处：《Biomedical and Environmental Sciences》2024年第12期1409-1420,共12页生物医学与环境科学（英文版）

基　　金：funded by the National Key R&D Program of China(2023YFC2605302).

摘　　要：Objective The present study aimed to evaluate the immunogenicity of BA.2 variant receptor binding domain(RBD)recombinant protein formulated with CpG 1826 plus alum dual adjuvant.Methods The BA.2 variant RBD(residues 308-548)fusing TT-P2 epitope was obtained from prokaryotic expression system,purification technology and dialysis renaturation,which was designated as Sot protein.The soluble Sot protein formulated with CpG 1826 plus alum dual adjuvant was designated as Sot/CA subunit vaccine and then the BALB/c mice were intramuscularly administrated with two doses of the Sot/CA subunit vaccine at 14-day interval(day 0 and 14).On day 28,the number of effector T lymphocytes secreting IFN-γand IL-4 in mice spleen were determined by enzyme-linked immunospot(ELISpot)assay.The serum IgG,IgG1 and IgG2a antibodies were examined by enzyme-linked immunosorbent assay(ELISA).In addition,the level of neutralizing antibodies(NAbs)induced by Sot/CA subunit vaccine was also evaluated by the microneutralization assay.Results The high-purity soluble Sot protein with antigenicity was successfully obtained by the prokaryotic expression,protein purification and dialysis renaturation.The Sot/CA subunit vaccine induced a high level of IgG antibodies and NAbs,which were of cross-neutralizing activity against SARS-CoV-2 BA.2 and XBB.1.5 variants.Meanwhile,Sot/CA subunit vaccine also induced a high level of effector T lymphocytes secreting IFN-γ(635.00±17.62)and IL-4(279.20±13.10),respectively.Combined with a decreased IgG1/IgG2a ratio in the serum,which indicating Sot/CA subunit vaccine induced a Th1-type predominant immune response.Conclusion The Sot protein formulated with CpG 1826 plus alum dual adjuvant showed that the excellent cellular and humoral immunogenicity,which provided a scientific basis for the development of BA.2 variant subunit vaccines and references for the adjuvant application of subunit vaccines.

关 键 词：SARS-CoV-2 RBD Subunit vaccine ADJUVANT IMMUNOGENICITY 

分 类 号：R392-33[医药卫生—免疫学]