Figure 5

ADP-ribosylation inhibits IL-2-induced phosphorylation of STAT5 by CTLL-2^ARTC2.2 cells and by ARTC2^+/+ Tregs.

(a) CTLL-2 and CTLL-2^ARTC2.2 cells were pre-incubated in the absence or presence of NAD⁺ before stimulation with IL-2 for 15 min. Cells were fixed and stained with fluorochrome-conjugated antibodies against phosphorylated STAT5 (pSTAT5). Control cells were incubated without NAD⁺ or IL-2. (b) CTLL-2 and CTLL-2^ARTC2.2 cells were pre-incubated with the ARTC2.2-blocking nanobody s+16a (nb) before addition of NAD⁺ and stimulation with IL-2. (c) Tregs were FACS-sorted from wildtype DEREG mice and incubated in the absence or presence of NAD⁺ before stimulation with IL-2 and staining for pSTAT5. Results are representative of two independent experiments.