Flow cytometric analysis of SEA binding to GM-CSF/IFN-γ–treated PMN. Open peaks represent staining of PMN when SEA is not present. Closed peaks represent staining of PMN after incubation with SEA. PMN were cultured for 44 hours in the absence or presence of 100 U/mL GM-CSF/IFN-γ before staining with SEA. HLA-DR expression by an HLA-DR^low responder (A) and an HLA-DR^high responder (C) correlated with the level of SEA binding to the HLA-DR^low responder (B) and HLA-DR^high responder (D). SEA binding to PMN cultured in the absence of GM-CSF/IFN-γ had the same MFI as the untreated control. Flow cytometric histograms represent 10,000 gated PMN.