Extended Data Fig. 1: Initial screen for anti-Cas9 donors by immunoblot.
From: Identification of preexisting adaptive immunity to Cas9 proteins in humans
Immunoblot analysis using healthy donor serum to determine if humans have IgG antibodies to Cas9 proteins. Serum derived from cord blood (labeled ‘CB’) or adults (labeled ‘A’) and immunoreactivity against purified Cas9 proteins are shown. S.a, S. aureus Cas9 ortholog; S.p, S. pyogenes Cas9 ortholog. Each lane with a detectable band was analyzed for volume and the score of Cas9 to the background was measured by dividing the volume of the Cas9 band by the volume of the background. Each immunoblot was scored as either positive (+) or negative (−) for immunoreactivity. To be considered serum-positive for antibodies against either Cas9 ortholog, a band must have been present at the correct size on the immunoblot and have had a ratio of 1.10 over the background. A ratio of 1 indicates that no band could be detected at the correct molecular weight.
