NADPH oxidase activity in COS7 transgenic cells. (A) Western blot analysis of COSPF-p67YFP (lane 1) and COSPF40-p67YFP (lane 2) cell lysates probed for expression of the indicated phox proteins. (B) Representative result of luminol assay for superoxide production in COS^phox cells during phagocytosis of IgG-opsonized SRBCs. □ indicates COSPF40-p67YFP; ◇, COSPF-p67YFP; and x, COS-WF. (C) Integrated RLU values for luminol assays of indicated cell lines (mean ± SD, n = 12).