Immunoreactive peptide maps of SARS-CoV-2

Serodiagnosis of SARS-CoV-2 infection is impeded by immunological cross-reactivity among the human coronaviruses (HCoVs) SARS-CoV-2, SARS-CoV-1, MERS-CoV, OC43, 229E, HKU1, and NL63. To study humoral immune responses specific to SARS-CoV-2, it is imperative to identify peptides that may enable discrimination between exposure to SARS-CoV-2 and other HCoVs. We used a high-density peptide microarray and plasma samples collected at two time points from 50 subjects with SARS-CoV-2 infection confirmed by qPCR, samples collected in 2004-2005 from 11 subjects with IgG antibodies to SARS-CoV-1, 11 subjects with IgG antibodies to other seasonal human coronaviruses (HCoV), and 10 healthy human subjects. The peptide microarrays consist of ~172000 12-mer peptide probes spanning whole viral genomes. This dataset consists of reactivity values for individual peptides from all 132 plasma samples for both IgG and IgM. Also made available is the correspondence key that provides a reference for all viral genome sequences that a peptide originated from.

Methods
Each peptide array is divided in 12 subarrays, with each subarray comprising ~172,000 twelve-amino acid (aa) nonredundant linear peptides that tile the proteomes of known HCoVs with 11 amino acid overlap. A total of 132 plasma samples were tested using eleven 12-plex peptide arrays. If there are three or more continuous reactive peptides (with reactivity values above the threshold of 10000) in samples, then those peptide sequences are reassembled to constitute an epitope. The length of an epitope depends on the number of such continuous reactive peptides.