Multifunctional CRISPR-Cas9 with engineered immunosilenced human T cell epitopes

Nat Commun. 2019 Apr 23;10(1):1842. doi: 10.1038/s41467-019-09693-x.


The CRISPR-Cas9 system has raised hopes for developing personalized gene therapies for complex diseases. Its application for genetic and epigenetic therapies in humans raises concerns over immunogenicity of the bacterially derived Cas9 protein. Here we detect antibodies to Streptococcus pyogenes Cas9 (SpCas9) in at least 5% of 143 healthy individuals. We also report pre-existing human CD8+T cell immunity in the majority of healthy individuals screened. We identify two immunodominant SpCas9 T cell epitopes for HLA-A*02:01 using an enhanced prediction algorithm that incorporates T cell receptor contact residue hydrophobicity and HLA binding and evaluated them by T cell assays using healthy donor PBMCs. In a proof-of-principle study, we demonstrate that Cas9 protein can be modified to eliminate immunodominant epitopes through targeted mutation while preserving its function and specificity. Our study highlights the problem of pre-existing immunity against CRISPR-associated nucleases and offers a potential solution to mitigate the T cell immune response.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Bacterial / blood
  • Antibodies, Bacterial / immunology
  • Antigen-Presenting Cells / immunology
  • CD8-Positive T-Lymphocytes / immunology*
  • CRISPR-Associated Protein 9 / genetics
  • CRISPR-Associated Protein 9 / immunology*
  • Cell Engineering / methods
  • Epitope Mapping / methods
  • Epitopes, T-Lymphocyte / genetics*
  • Epitopes, T-Lymphocyte / immunology
  • Genetic Therapy / adverse effects
  • Genetic Therapy / methods
  • HEK293 Cells
  • HLA-A Antigens / immunology
  • Healthy Volunteers
  • Humans
  • Lymphocyte Activation / genetics
  • Lymphocyte Activation / immunology
  • Mutagenesis / immunology*
  • Precision Medicine / adverse effects
  • Precision Medicine / methods
  • Streptococcus pyogenes / genetics
  • Streptococcus pyogenes / immunology*


  • Antibodies, Bacterial
  • Epitopes, T-Lymphocyte
  • HLA-A Antigens
  • CRISPR-Associated Protein 9