Stanford study raises Cas9 immunogenicity concerns

A new study published Friday on the preprint server bioRxiv suggests many people may have pre-existing immunity to the Cas9 enzymes commonly used in CRISPR-based therapeutics, raising questions about whether CRISPR-Cas9 (CRISPR-associated protein 9) based therapies can be safely delivered to patients.

In the paper, Stanford University Associate Professor Matthew Porteus tested the hypothesis that because humans are exposed to Staphylococcus aureus and Streptococcus pyogenes as pathogenic and commensal bacteria, they might have pre-existing immunity to the Cas9 proteins isolated from those species for CRISPR-Cas9 therapies. S. aureus and S. pyogenes Cas9 are the most commonly used and studied CRISPR-associated enzymes...