Investigation of Cas9 antibodies in the human eye

• Published in: Nature communications Vol. 13; no. 1; p. 1053
• Main Authors: Toral, Marcus A., Charlesworth, Carsten T., Ng, Benjamin, Chemudupati, Teja, Homma, Shota, Nakauchi, Hiromitsu, Bassuk, Alexander G., Porteus, Matthew H., Mahajan, Vinit B.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 25.02.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 631/250/2520; 631/337/4041; 64/60; 692/698/1688/512/2613; 82/1; Animals; Antibodies; Antibodies - metabolism; Bacterial diseases; Biopsy; Clinical trials; CRISPR; CRISPR-Associated Protein 9 - metabolism; CRISPR-Cas Systems; Cytokines; Enzyme-linked immunosorbent assay; Eye (anatomy); Gene therapy; Humanities and Social Sciences; Humans; Immune system; Immunity; Immunization; Infections; Lymphocytes T; Mice; multidisciplinary; Proteins; Science; Science (multidisciplinary); Streptococcus infections; Streptococcus pyogenes - metabolism; T-Lymphocytes
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-28674-1

Preexisting immunity against Cas9 proteins in humans represents a safety risk for CRISPR–Cas9 technologies. However, it is unclear to what extent preexisting Cas9 immunity is relevant to the eye as it is targeted for early in vivo CRISPR–Cas9 clinical trials. While the eye lacks T-cells, it contains antibodies, cytokines, and resident immune cells. Although precise mechanisms are unclear, intraocular inflammation remains a major cause of vision loss. Here, we used immunoglobulin isotyping and ELISA platforms to profile antibodies in serum and vitreous fluid biopsies from human adult subjects and Cas9-immunized mice. We observed high prevalence of preexisting Cas9-reactive antibodies in serum but not in the eye. However, we detected intraocular antibodies reactive to S. pyogenes -derived Cas9 after S. pyogenes intraocular infection. Our data suggest that serum antibody concentration may determine whether specific intraocular antibodies develop, but preexisting immunity to Cas9 may represent a lower risk in human eyes than systemically. Pre-existing antibodies against Cas9 proteins represent a potential issue for gene therapies, including those targeting the eye. Here the authors assess the presence of intraocular antibodies, and show that Cas9 antibodies were prevalent in human serum but not the eye, unless prior bacterial infection occurred.