Modulating Human Cas9-Specific Host Immune Response

As CRISPR technology is moving to the clinic, pre-existing immunity to SpCas9 in healthy individuals is a reasonable concern. We created modified Cas9 constructs by mutating bioinformatically defined human immunogenic epitopes and tested their function in comparison with wild-type Cas9. we examined variants’ nuclease activity by targeting EMX-1 locus. Then, to investigate whether these variants retain the transcriptional modulation capacity, we targeted two different endogenous genes (TTN and MIAT).

Our data indicate that mutated Cas9 proteins recognize and bind their target DNA; leading to enhanced endogenous target gene expression or introduction of indels.