Fig. 3: SLAMF6 inhibits T cell activation and killing.
Expression of SLAMF6 by flow cytometry in wild-type and SLAMF6-knockout cells generated from the AML cell lines KG-1 (a) and HNT-34 (b) by CRISPR–Cas9. SLAMF6 KO (A) and SLAMF6 KO (B) denote SLAMF6-knockout cells generated by two different crRNAs. SLAMF6 WT denotes SLAMF6 wild-type cells mock-electroporated with a crRNA targeting the firefly luciferase gene. c–e, T cell-mediated killing of KG-1 cells (P = 0.029 for KO (A) and P = 0.029 for KO (B)) (c), frequency of activated T cells (P = 0.029 for KO (A) and P = 0.029 for KO (B)) (d) and total number of T cells (P = 0.029 for KO (A) and P = 0.029 for KO (B)) (e) in 72-h coculture assay with primary human T cells and wild-type and SLAMF6-knockout cells. Values were normalized to wild-type control. Data are shown as the mean ± s.e.m. (n = 4 T cell donors; two-sided Mann–Whitney U-test). f–h, T cell-mediated killing of HNT-34 cells (P = 0.029 for KO (A) and P = 0.029 for KO (B)) (f), frequency of activated T cells (P = 0.029 for KO (A) and P = 0.314 for KO (B)) (g) and total number of T cells (P = 0.314 for KO (A) and P = 0.029 for KO (B)) (h) in 72-h coculture assay with primary human T cells and wild-type and SLAMF6-knockout cells. Values were normalized to the wild-type control. Data are shown as the mean ± s.e.m. (n = 4 T cell donors; two-sided Mann–Whitney U-test). i, Representative T cell activation in coculture assay with KG-1, as determined by surface expression of CD25 and CD69 on CD4+ and CD8+ T cells by flow cytometry (one representative donor of four). j, Expansion of wild-type and SLAMF6-knockout KG-1 cells in the absence of T cells. Cell numbers after 72 h of culture were normalized to the wild-type control. Data are shown as the mean ± s.e.m. (n = 6 experiments; two-sided Mann–Whitney U-test, P = 0.054 for KO (A) and P = 0.372 for KO (B)). NS, not significant. k, Expansion of wild-type and SLAMF6-knockout HNT-34 cells in the absence of T cells. Cell numbers after 72 h of culture were normalized to the wild-type control. Data are shown as the mean ± s.e.m. (n = 6 experiments; two-sided Mann–Whitney U-test, P = 0.999 for KO (A) and P = 0.314 for KO (B)).
