Figure 5.

TIGIT blockade boosts functional responsiveness of CD56^dim NK cells of OC patients with a baseline reactivity against SKOV-3 cells. (a) Schematic overview of the mouse experiment. (b) Bioluminescence imaging (BLI) signal of SKOV-3 tumor-bearing mice over time in “control”, “NK” only and “NK+TIGIT” blockade groups (n = 15 per group). (c) Total number of peritoneal NK cells harvested from “NK” only and “NK+TIGIT” blockade groups as measured by flow cytometry (average of bead and volume count cytoflex). (d) Percent CD107a (top graph) and IFNγ (bottom graph) from peritoneal NK cells harvested from “NK” only and “NK+TIGIT” groups which were re-stimulated ex-vivo with SKOV-3 for 4 h in the presence of low dose rhIL-15. (e) Percent CD107a (top graph) and IFNγ (bottom graph) from peritoneal NK cells harvested from “NK” only group re-stimulated with SKOV-3 in the presence of low dose rhIL-15 in combination with TIGIT, DNAM-1, TIGIT/DNAM-1 co-blockade or corresponding isotype control(s). (f-g) Percentage CD107a⁺ and IFNγ⁺ CD56^dim NK cells upon overnight treatment with low dose rhIL-15 (1 nM) and subsequent 4 h stimulation with K562 (f) or SKOV-3 (g). Based on a cutoff of 10% CD107a expression on CD56^dim NK cells co-cultured with SKOV-3 and rhIL-15 (without additional treatment) patients were subdivided in responder (≥10%) and non-responder (<10%) cohorts. Cumulative data of healthy donors (HD; n = 10) and ovarian cancer patients (Pt; n = 9) are shown with median. The Mann-Whitney test was used for statistical analysis, * p < .05. (h) CD56^dim NK cells positive for CD107a and IFNγ after 4 h stimulation with SKOV-3 target cells, low dose rhIL-15 (1 nM), and TIGIT and/or DNAM-1 blockade or matching isotype controls. Cumulative data shown for SKOV-3 responders only (lines indicate mean, n = 6). A One-Way ANOVA with Bonferroni correction was used for statistical analysis, * p < .05 and *** p < .001