NK-cell recognition of HLA class I–deficient primary human T cells. (A) Experimental setup for NK-cell recognition assay. (B) Representative flow-cytometric analysis of CD107a⁺ NK cells (percentage of living CD56⁺ CD8⁻ lymphocytes) after 5 hours of coincubation with indicated target T cells, K562 cells or PMA/Iono; cells were sorted for successful editing. (C) Quantification of data shown in panel B; n = 3 technical replicates; statistical testing was done using an unpaired 2-tailed t test and results are only shown for comparison of WT and B2M KO T cells; mean ± SD; ∗∗∗P < .001.