Detection of SARS-CoV-2 Specific Memory B cells to Delineate Long-Term
COVID-19 Immunity
Abstract
Background: The ongoing COVID-19 pandemic, caused by the novel
coronavirus SARS-CoV-2, represents a serious worldwide health concern. A
deeper understanding of the immune response to SARS-CoV-2 will be
required to refine vaccine development and efficacy as well as to
evaluate long-term immunity in convalescent patients. With this in mind,
we investigated the formation of SARS-CoV-2 specific BMEMORY cells from
patient blood samples. Methods: A standard flow cytometry-based protocol
for the detection of SARS-CoV-2 specific B cells was applied using
fluorochrome-coupled SARS-CoV-2 spike (S) full-length protein. Cohorts
of 26 central European convalescent mild/moderate COVID-19 patients and
14 healthy donors were assessed for the levels of SARS-CoV-2 S- specific
BMEMORY cells. Results: Overall B cell composition was not affected by
SARS-CoV-2 infection in convalescent patients. Our analysis of
SARS-CoV-2 specific BMEMORY cells in samples collected at different time
points revealed that S-protein specific B cells remain in peripheral
blood at least up to 6 months after COVID-19 diagnosis. Conclusions:
Detection of SARS-CoV-2 specific BMEMORY cells may improve our
understanding of the long-term adaptive immunity in response to
SARS-CoV-2, allowing for an improved public health response and vaccine
development during the COVID-19 pandemic. Further validation of the
study in larger and more diverse populations and a more extended
observation period will be required.