CD300a TASR enhances CAR T-cell functional potency under allogeneic immune pressure. (A) Nonviral multiplexed targeted integration of human T cells to coexpress cloaking and anti-CD19 CAR transgenes while ablating HLA-I and TCRαβ expression. (B) Phenotype of 3 engineered CAR T cells by flow cytometry expressing the indicated cloaking transgene at B2M locus, gated live single cells. The same anti-CD19 CAR is used for all CAR T cells. (C) B-cell lysis assay for engineered CAR T-cell therapy containing the indicated cloaking transgene against the indicated PBMC donors (bottom row). N = 2 technical replicate curves per condition. Phenotype of NK cells from the respective PBMC donor (top row). (D) Cytotoxicity of indicated cloaked anti-CD19 CAR T cell against CD19-expressing Raji cells. The gray color indicates no CAR control T cells contain CD300a TASR integrated into the B2M loci without anti-CD19 CAR. N = 3 technical replicate curves per condition. (E) NK challenge of cloaked anti-CD19 CAR T cells containing the indicated cloaking transgene with a 2A^dom and 2C^dom NK donor. N = 3 technical replicates curves per condition.