Extended Data Fig. 8: Generation of NALM6 cell lines with graded CD19 expression.

a, Genotype of edited CD19 locus in NALM6^med (top) and NALM6^low (bottom) cells. NALM6^med and NALM6^low cells were obtained by monoallelic and biallelic disruption of the Cd19 gene, respectively, using the CRISPR–Cas9 system. One of the alleles encodes a stop codon (asterisk); the second allele codes for a variant CD19 containing an amino acid substitution (Mut-1, 2 or 3aa). b, Prediction of the cleavage of CD19 protein sequence of the functional allele (Mut-3aa) in NALM6^low cells (top) and the wild-type (WT) protein sequence (bottom) using signal 4.1 server. Cd19 gRNA was designed to target Cd19 exon 1, next to the site of cleavage of signal peptide. Data were obtained by deep sequencing. c, MFI of CD19 on the surface of NALM6 cells (NALM6^wt), NALM6^med cells, NALM6^low cells and CD19-knockout NALM6 cells (NALM6^KO) (n = 3 independent experiments). d, MFI of CD22 on the surface of NALM6 cells, NALM6^med cells and NALM6^low cell (n = 3 independent experiments). Data are mean ± s.e.m.