Figure 9. Serology of SARS-CoV-2 infected deer.

Detection of SARS-CoV-2 nucleocapsid protein (A), and the receptor binding domain (B) by indirect ELISA tests. The cut-off was determined by averaging the OD of negative serum + 3X the standard deviation as indicated by the dotted line. All samples with resulting OD values above this cut-off were considered positive. (C) Virus neutralizing antibodies detected in serum are shown as log2 of the reciprocal of the neutralization serum dilution. Sera were tested starting at 1:40 dilution indicated by the dotted line. (D) Sera were also tested against bovine coronavirus (BCoV) spike protein ELISA, and included both positive (C+) and negative (C−) controls. Deer sera collected from a previous epizootic hemorrhagic disease virus vaccine study were used as negative controls (36).