SHIP+/+ but not −/− GM- DC-induced T cell suppression is mediated by IFNγ-dependent NO production.

<p>WT splenocytes were stimulated with soluble αCD3+ αCD28 Abs and incubated with SHIP+/+ or −/− GM-DCs (50×10³) for 72 hrs. <b>A)</b> Left panel, relative percent suppression of proliferation in the absence (ctrl) or presence of 25 µg/ml PTIO, 0.5 mM–2.5 mM L-NMMA or 25 µg/ml PTIO +0.5 mM L-NMMA). Right panel, NO production using the same concentrations of PTIO and/or L-NMMA. <b>B)</b> WT splenocytes were stimulated with soluble αCD3+ αCD28 Abs and incubated with SHIP+/+ or −/− GM-DCs (50×10³) ±10 µg/ml neutralizing αIFNγ. Left panel, percent suppression of T cell proliferation. Right panel, NO production. Data shown are mean ± SEM of triplicate cultures and are representative of 3 independent experiments. *p<0.05 relative to genotype control, ns = not significantly different. ▾ indicates level is below detection.