Extended SARS-CoV-2 RBD booster vaccination induces humoral and cellular immune tolerance in mice

Feng-Xia Gao; Rui-Xin Wu; Mei-Ying Shen; Jing-Jing Huang; Ting-Ting Li; Chao Hu; Fei-Yang Luo; Shu-Yi Song; Song Mu; Ya-Nan Hao; Xiao-Jian Han; Ying-Ming Wang; Luo Li; Sheng-Long Li; Qian Chen; Wang Wang; Ai-Shun Jin

doi:10.1016/j.isci.2022.105479

Extended SARS-CoV-2 RBD booster vaccination induces humoral and cellular immune tolerance in mice

iScience. 2022 Dec 22;25(12):105479. doi: 10.1016/j.isci.2022.105479. Epub 2022 Nov 2.

Authors

Feng-Xia Gao^{1

2}, Rui-Xin Wu^{1

2}, Mei-Ying Shen³, Jing-Jing Huang^{1

2}, Ting-Ting Li^{1

2}, Chao Hu^{1

2}, Fei-Yang Luo^{1

2}, Shu-Yi Song^{1

2}, Song Mu^{1

2}, Ya-Nan Hao^{1

2}, Xiao-Jian Han^{1

2}, Ying-Ming Wang^{1

2}, Luo Li^{1

2}, Sheng-Long Li^{1

2}, Qian Chen^{1

2}, Wang Wang^{1

2}, Ai-Shun Jin^{1

2}

Affiliations

¹ Department of Immunology, College of Basic Medicine, Chongqing Medical University, ChongQing 400010, China.
² Chongqing Key Laboratory of Basic and Translational Research of Tumor Immunology, Chongqing Medical University, ChongQing 400010, China.
³ Department of Endocrine Breast Surgery, the First Affiliated Hospital of Chongqing Medical University, ChongQing 400010, China.

Abstract

The repetitive applications of vaccine boosters have been brought up in face of continuous emergence of SARS-CoV-2 variants with neutralization escape mutations, but their protective efficacy and potential adverse effects remain largely unknown. Here, we compared the humoral and cellular immune responses of an extended course of recombinant receptor binding domain (RBD) vaccine boosters with those from conventional immunization strategy in a Balb/c mice model. Multiple vaccine boosters after the conventional vaccination course significantly decreased RBD-specific antibody titers and serum neutralizing efficacy against the Delta and Omicron variants, and profoundly impaired CD4⁺ and CD8⁺T cell activation and increased PD-1 and LAG-3 expressions in these T cells. Mechanistically, we confirmed that extended vaccination with RBD boosters overturned the protective immune memories by promoting adaptive immune tolerance. Our findings demonstrate potential risks with the continuous use of SARS-CoV-2 vaccine boosters, providing immediate implications for the global COVID-19 vaccination enhancement strategies.

Keywords: Cell biology; Immune response; Microbiology.