Abstract
The emergence of the novel coronavirus, SARS-CoV-2, during the COVID-19 pandemic prompted investigations into pre-existing immunity in human populations. Despite being a new coronavirus, individuals had previous exposure to common seasonal human coronaviruses. In this study, we examined SARS-CoV-2-specific memory B cells in six pre-pandemic Lassa virus-infected patients from West Africa.
By incorporating a SARS-CoV-2 Spike Antigen (WA-1 strain) into a broader antigen panel that included Lassa virus GPC and a control, we identified and sorted antigen-positive B cells. Further analysis revealed a distinct population of SARS-CoV-2-specific memory B cells. Native paired monoclonal antibody (mAb) sequences were recovered from 598 SARS-CoV-2 Spike-positive B cells, demonstrating a surprisingly high frequency of pre-existing SARS-CoV-2-specific B cells.
Remarkably, Spike-specific mAbs were recovered from all six donors, each contributing to at least one expanded clonal lineage. Notably, most IgM antibodies belonged to the same lineages. These findings suggest a notable prevalence of pre-existing immunity to SARS-CoV-2 in pre-pandemic patients, potentially influencing susceptibility to the virus and contributing to adverse COVID-19 outcomes. This study provides insights for risk management and supports the development of universal coronavirus vaccines by highlighting the complex interplay between pre-existing immunity and susceptibility to SARS-CoV-2.
