Identification of preexisting adaptive immunity to Cas9 proteins in humans

Abstract

The CRISPR-Cas9 system is a powerful tool for genome editing, which allows the precise modification of specific DNA sequences. Many efforts are underway to use the CRISPR-Cas9 system to therapeutically correct human genetic diseases [1][2][3][4][5][6] . The most widely used orthologs of Cas9 are derived from Staphylococcus aureus and Streptococcus pyogenes 5,7 . Given that these two bacterial species infect the human population at high frequencies 8,9 , we hypothesized that humans may harbor preexisting adaptive immune responses to the Cas9 orthologs derived from these bacterial species, SaCas9 (S. aureus) and SpCas9 (S. pyogenes). By probing human serum for the presence of anti-Cas9 antibodies using an enzyme-linked immunosorbent assay, we detected antibodies against both SaCas9 and SpCas9 in 78% and 58% of donors, respectively. We also found anti-SaCas9 T cells in 78% and anti-SpCas9 T cells in 67% of donors, which demonstrates a high prevalence of antigen-specific T cells against both orthologs. We confirmed that these T cells were Cas9-specific by demonstrating a Cas9-specific cytokine response following isolation, Reprints and permissions information is available at www.nature.com/reprints.

Engineered amphiphilic peptides enable delivery of proteins and CRISPR-associated nucleases to airway epithelia

“…5) are encouraging. Despite no evidence of short-term toxicity, future studies should address the immunogenicity of specific therapeutic cargoes 71 . Further investigations will also be required to establish the relationship between the unique physicochemical properties of peptide sequences that provide specific molecular interactions depending upon the nature of protein cargo and target cell type 35,72 .…”

Regulated control of gene therapies with a drug induced switch

“…While gene editing approaches provide an enormous opportunity for altering or removing disease alleles, prolonged expression of the editing machinery from viral vectors could be problematic. The editing enzymes are foreign proteins and may induce immune responses, and prolonged gene expression would increase opportunities for off-target editing 15,16 . We tested the utility of the X on system to regulate editing, using huntingtin (HTT), a target for gene silencing approaches for Huntington's disease (HD) 17 , as an example.…”

Evaluating the Probability of CRISPR-based Gene Drive Contaminating Another Species

“…pyogenes is a facultative pathogenic bacteria mostly restricted to humans, with about 10-20% of the population being asymptomatic carriers (Shaikh et al 2010;Roberts et al 2012) . It is thus no surprise that recent investigations have found anti-Cas9 antibodies and Cas9-reactive T cells in several human populations (Charlesworth et al 2019;Wagner et al 2019) . It is thus possible that certain humans are immune to gene drives, and future studies will undoubtedly shed light on this question.…”