Human peripheral blood mononuclear cells were unstimulated (light orange filled histogram) or treated with PMA and Calcium ionomycin, then stained with Mouse Anti-Human IL‑26/AK155 Monoclonal Antibody (Catalog # MAB13751, dark orange filled histogram) or isotype control (Catalog # MAB002, open histogram), followed by Phycoerythrin-conjugated Anti-Mouse IgG F(ab')2 Secondary Antibody (Catalog # F0102B). To facilitate intracellular staining, cells were fixed with paraformaldehyde and permeabilized with saponin.