# Define and minimize the immunogenicity of CRISPR-Cas nucleases

> **NIH NIH F31** · ST. JUDE CHILDREN'S RESEARCH HOSPITAL GRADUATE SCHOOL OF BIOMEDICAL SCIENCES, LLC · 2021 · $37,236

## Abstract

Project Abstract
 In vivo CRISPR-Cas genome editing has the potential to transform human medicine by directly correcting
disease-causing mutations in affected cells in the body. CRISPR Cas nucleases allow for site-specific and
efficient modifications of a wide range of biomedically important cellular targets. Cas9 from Staphylococcus
aureus (S.aureus; SaCas9) was the first orthologue discovered to be active in mammalian cells that is small
enough to be encoded in an AAV vector. Previous studies, using SaCas9 encoded in AAV vectors to treat
Duchenne's Muscular Dystrophy (DMD) in young dogs has resulted in the functional correction of the disease.
Demonstrating, the proof-of-concept that CRISPR can halt the progression of DMD and restore function and
thus, be used successfully in in vivo studies.
 However, one major concern that threatens the durability of promising in vivo genome editing therapeutic
strategies using Cas9, is the potential for immune rejection of Cas9 expressing edited cells. Preexisting adaptive
immunity to Cas9 variant S.aureus, a common human pathogen, has been reported. Therefore, human cells that
have been therapeutically treated with SaCas9 are likely to elicit an adaptive memory immune response and
trigger killing of Cas9-expressing cells by cytotoxic T-cells.
 While SaCas9 specific T cells have been identified, the adaptive immune response to SaCas9 has not been
fully characterized. The primary human T-cell response to SaCas9 will be readdressed, by probing human serum
of healthy and HLA (Human Leukocyte Antigen)-typed human blood donors (Aim 1). In addition, to identify novel
and non-immunogenic SaCas9 variants we will conduct a comprehensive mutational screen to elucidate the
structure-function relationship of SaCas9. This will lay groundwork for generating a universal SaCas9 that is
potentially non-immunogenic for a variety of HLA-types (Aim 2).
 The proposed work will broaden the knowledge in the gene editing community and expand its implications
for future clinical application of CRISPR/Cas in gene therapy.

## Key facts

- **NIH application ID:** 10315725
- **Project number:** 1F31AI157225-01A1
- **Recipient organization:** ST. JUDE CHILDREN'S RESEARCH HOSPITAL GRADUATE SCHOOL OF BIOMEDICAL SCIENCES, LLC
- **Principal Investigator:** Andrea Lee
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $37,236
- **Award type:** 1
- **Project period:** 2021-12-23 → —

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10315725

## Citation

> US National Institutes of Health, RePORTER application 10315725, Define and minimize the immunogenicity of CRISPR-Cas nucleases (1F31AI157225-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10315725. Licensed CC0.

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