Fig. 1. IFN-γ priming is required to trigger RIPK1-dependent caspase-8 activation in neutrophils following Y. pseudotuberculosis infection in vitro.

A–G Bone marrow neutrophils (BMNs) were left unstimulated or primed with 100 ng/ml LPS, 100 ng/ml IFN-γ or both LPS and IFN-γ for 3 h prior to infection with Y. pseudotuberculosis (Yp) at a multiplicity of infection(MOI) of 5 for 4 h. Where indicated, cells were treated with 50 μM Necrostatin-1s (Nec-1s) 20–30 min before infection. A Mixed supernatant and cell extracts were examined by immunoblotting. Three membranes were used for immunoblotting (i, ii, iii). B–F LDH release and G IL-1β secretion were measured at the end of the infection. B–G Data are represented as mean + SEM cell stimulation from at least three independent experiments. *P < 0.05, **P < 0.01 and ***P < 0.001.