Next-generation B cell ImmunoSpot® assays permit in-depth assessment of the B cell response elicited by SARS-CoV-2 infection and/or COVID-19 mRNA vaccination

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Presentation Time: 03:15 PM - 04:30 PM
Poster Board Number: B822
Abstract ID: 4915

Presenting Author:
Greg A Kirchenbaum , Director of Basic B cell Research at Cellular Technol., Northumbria Univ.

Abstract:

The affinity distribution of antigen-specific B_mem in the body is a critical variable that defines an individual’s ability to rapidly generate protective antibody specificities. Moreover, defining the Ig class/subclass usage of such antigen-specific B_mem is also critical since it forecasts the anamnestic response to be engaged upon antigen re-encounter. Here, we leveraged multiplexed ImmunoSpot to comprehensively define the magnitude and Ig class/subclass usage of the SARS-CoV-2 S-specific B_mem following infection and/or multiple COVID-19 mRNA vaccinations. Beyond evidencing past SARS-CoV-2 infection more reliably than assessment of plasma IgG reactivity against the nucleocapsid protein, direct assessment of B_mem provided insights into their affinity distribution and cross-reactivity profiles against emerging variants such as Delta and Omicron. Following stimulation of PBMC to transition resting B_mem into antibody-secreting cells, our studies entailed tracking of the S-specific B_mem compartment in subjects as their immune histories became increasingly more complex. Of note, our next-generation ImmunoSpot assay approaches evidenced improved functional affinity at single-cell resolution. Collectively, such B cell ImmunoSpot assays offer tremendous value for future B cell immune monitoring efforts owing to their ease of implementation, applicability to essentially any antigenic system, economy of PBMC utilization and suitability for regulated testing.