High prevalence of Streptococcus pyogenes Cas9-reactive T cells within the adult human population

The discovery of the highly efficient site-specific nuclease system CRISPR-Cas9 from Streptococcus pyogenes has galvanized the field of gene therapy1,2. The immunogenicity of Cas9 nuclease has been demonstrated in mice3,4. Preexisting immunity against therapeutic gene vectors or their cargo can decrease the efficacy of a potentially curative treatment and may pose significant safety issues3-6. S. pyogenes is a common cause for infectious...