Fig. 3.

Representative AIR array images of (A) 5% FBS; (B) 10% PNHS; (C) a negative single-donor sample, and (D) one convalescent serum sample. Strong responses to SARS-CoV-2 antigens are readily observed in (D), but not in (A), (B), or (C), while responses to circulating coronaviruses HKU, OC43, and 229E are observed in (B), (C), and (D). In each case, samples were diluted 1:20 in Adarza diluent, and incubated with the arrays overnight at 4 °C. See Fig. 1 for key to the array. All arrays in this figure were imaged at an exposure of 100 ms.