Dangi T, Sanchez S, Lew MH, Awakoaiye B, Visvabharathy L, Richner JM, Koralnik IJ, Penaloza-MacMaster P. Pre-existing immunity modulates responses to mRNA boosters.
Cell Rep 2023;
42:112167. [PMID:
36857186 PMCID:
PMC9928730 DOI:
10.1016/j.celrep.2023.112167]
[Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 12/19/2022] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
mRNA vaccines are effective in preventing severe COVID-19, but breakthrough infections, emerging variants, and waning immunity warrant the use of boosters. Although mRNA boosters are being implemented, the extent to which pre-existing immunity influences the efficacy of boosters remains unclear. In a cohort of individuals primed with the mRNA-1273 or BNT162b2 vaccines, we report that lower antibody levels before boost are associated with higher fold-increase in antibody levels after boost, suggesting that pre-existing antibody modulates the immunogenicity of mRNA vaccines. Our studies in mice show that pre-existing antibodies accelerate the clearance of vaccine antigen via Fc-dependent mechanisms, limiting the amount of antigen available to prime B cell responses after mRNA boosters. These data demonstrate a "tug of war" between pre-existing antibody responses and de novo B cell responses following mRNA vaccination, and they suggest that transient downmodulation of antibody effector function may improve the efficacy of mRNA boosters.
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