Deep Immune Repertoire Analysis of SARS Antibodies

ASHG 2022, Los Angeles, CA

Deep immune repertoire analysis of SARS-CoV-2 antibodies from a vaccinated human patient via mass-spectrometry and Loop synthetic long reads.

N. Castellana1, T. Lima1, S. Bonissone1, A. Patel1 , R. Carson1, Ryan Kelley2, Abhai Sawkar2, Kyle Metcalf2
1Abterra BioSci.s, Inc., San Diego, CA
2Element BioSci.s, San Diego, CA

The immune system of an individual contains the capacity to produce trillions of unique antibody proteins. Identifying the antibodies involved in a particular immune response is key to understanding the human immune response to disease and crucial for future antibody therapeutic development. Enrichment of serum antibodies for reactivity followed by sequencing via mass-spectrometry can be used to identify antibodies, but requires a candidate set of targets for accurate identification. Deep immune repertoire analysis by sequencing of B cells can provide this set but is currently expensive and low coverage. The combination of synthetic long read technology and high-throughput short read sequencing is a cost-efficient method to enable deep immune repertoire analysis. In this study, blood was collected from a human donor vaccinated against SARS-CoV-2. One-hundred million B cells were isolated from whole blood and sorted based on reactivity to the SARS-CoV-2 receptor binding domain (RBD), with collection of both reactive and non-reactive B cells. Loop Genomics synthetic long reads and the Aviti sequencing platform were used to sequence antibody variable regions of both samples. Candidates were identified from those sequences enriched in the reactive B cells. Serum antibodies from the same donor were enriched for reactivity to RBD and spike trimer, analyzed by mass spectrometry, and matched to the NGS-derived antibody repertoire to identify antibodies critical to the SARS-CoV-2 immune response.

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