Molecular Detection of SARS-CoV-2 in Formalin Fixed Paraffin Embedded Specimens

Xiankun Zeng; Jun Liu; April Babka; Brian Kearney; Sheli Radoshitzky; Jens Kuhn

Identification of antibodies suitable for detection of SARS-CoV-2 by IHC and IFA in FFPE 81 specimens. To identify antibodies that can be used to detect SARS-CoV-2 in human and animal 82 tissues, we searched for commercially available SARS-CoV antibodies that recognize epitopes 83 that are likely conserved in SARS-CoV-2. We identified six antibodies, including three rabbit 84 polyclonal antibodies, against SARS-CoV S, one rabbit polyclonal antibody against SARS-CoV 85 nucleocapsid protein (NP), and one rabbit and one mouse monoclonal antibody against CoV NP that may cross react with SARS-CoV-2 (Supplemental Table 1 ). Additionally, we also 87 identified a rabbit monoclonal antibody against SARS-CoV-2 S (Supplemental Table 1 ). To SARS-CoV-2 detection in FFPE specimens 7 use of the RNAscope ISH assay to detect SARS-CoV-2 RNA in FFPE cell pellets using three 103 probes: two probes binding the SARS-CoV-2 positive-sense (genomic) RNA and one probe 104 binding the negative-sense (replicative intermediate) RNA (Figure 2A -F, Supplemental Table 2) .