CD56⁺ILC1-like cells are cytotoxic effectors regulated by the NKp30, NKp80, TRAIL, and HLA-E pathways. (A) Extracellular flow cytometry analysis of NK receptor expression in ILCP, CD56⁺ ILC1-like cells, and cNKs (n = 4-18). (B) Intracellular flow cytometry was performed using HD PBMCs to assess CD56⁺ ILC1-like cell production of granzyme A (n = 15), granzyme B (n = 15), granzyme K (n = 12), granzyme M (n = 12), perforin (n = 12), and granulysin (n = 12). (C) Extracellular flow cytometry was performed after a 4-hour coculture of ILC/NK-enriched PBMCs with K562 (ratio E:T 1:1), anti-CD107a, and Golgistop to assess CD56⁺ ILC1-like cell degranulation (n = 16). (D) Specific lysis of the K562 tumor cell line by CD56⁺ ILC1-like cells, cNKs, and helper ILCs (results in duplicate). (E) Specific lysis of the U937, K562, and BJAB tumor cell lines by CD56⁺ ILC1-like cells (results in duplicate). (F) Specific lysis by CD56⁺ ILC1-like cells of K562 (ratio E:T 20:1), BJAB (ratio E:T 20:1), and U937 (ratio E:T 10:1) tumor cell lines in the presence of anti-DNAM-1, anti-NKp30, and anti-NKp80 blocking antibodies or TRAIL decoy receptor. (G) Specific lysis of wild-type (WT) or HLA-E–transfected 721.221 tumor cell lines by CD56⁺ ILC1-like cells (results in triplicate). One dot = 1 donor. Statistical tests used for analyses: panel B: Mann-Whitney unpaired U test; panel C: Wilcoxon paired t test, panel G: multiple Holm-Sidak t tests. *P < .05, **P < .01, ***P < .001, ****P < .0001.