Methods and compositions for anti-cd45 based non-genotoxic conditioning

A base editor system comprising a nucleobase editor polypeptide, or a polynucleotide encoding the nucleobase editor polypeptide, wherein the nucleobase editor polypeptide comprises a nucleic acid programmable DNA binding protein (napDNAbp) domain and a deaminase domain, and a guide RNA (gRNA), or a polynucleotide encoding the gRNA, wherein the gRNA targets a polynucleotide encoding a cluster of differentiation 45 (CD45) polypeptide, thereby introducing a missense mutation in a CD45 polynucleotide, wherein the missense mutation is in a portion of the polynucleotide encoding the extracellular domain and/or in fibronectin domain 1 to domain 4 of the CD45 polypeptide, and wherein the missense mutation is associated with a reduction in binding of an anti-CD45 antibody to the CD45 polypeptide expressed by the edited HSPC.

A method of producing an edited hematopoietic stem or progenitor cell (HSPC) for the treatment of a disease or condition, the method comprising:

• (a) expressing in the hematopoietic stem cell or progenitor thereof a nucleobase editor polypeptide, wherein the nucleobase editor polypeptide comprises an SpCas9 polypeptide having specificity for a protospacer adjacent motif selected from NRCH and NGC, wherein “N” is A, T, G, or C, “R” is A or G, and “H” is A, C, or T, and an adenosine deaminase domain, wherein the adenosine deaminase domain comprises TadA*8.20, TadA-8e, or TadA*8.20 with the amino acid alterations S82T, Y147D, F149Y, T166I, and D167N;
• and
• (b) contacting the hematopoietic stem cell or progenitor thereof with gRNA4630 or gRNA2696, thereby introducing a missense mutation in a CD45 polynucleotide in the cell, wherein the missense mutation results in an E259G alteration to the CD45 polypeptide encoded by the CD45 polynucleotide.